BTO - British Trust for Ornithology - International

Leakage of plastics and other debris from landfills to a highly protected lake by wintering gulls

VIOLA.ROSS-SMITH — Fri, 26 Jan 2024 15:58:02 +0000

The Cuckoo cohort of 2024 takes flight!

Martín Vélez, V., Cano-Povedano, J., Cañuelo-Jurado, B., López-Calderón, C., Céspedes, V., Ros, M., Sánchez, M.I., Shamoun-Baranes, J., Müller, W., Thaxter, C.B., Camphuysen, C.J., Cózar & Green, A.J. Waste Management 10.1016/j.wasman.2024.01.034

General context

Gulls ingest plastic and other litter while foraging in open landfills, because organic matter is mixed with other debris. Therefore, gulls are potential biovectors of plastic pollution into natural habitats, especially when they concentrate in wetlands for roosting.

Novelty

We quantified, for the first time, the flow of plastic and other anthropogenic debris from open landfills to a natural lake via the movement of gulls. We focused on Fuente de Piedra, an inland closed-basin lake in Spain that is internationally important for biodiversity.

Methodology

In 2022, we sampled gull pellets regurgitated in the lake by lesser black-backed gulls Larus fuscus that feed on landfills, as well as their faeces, then characterized and quantified debris particles of ≥0.5 mm. By combining GPS and census data from 2010 to 2022, together with plastic quantification based on FTIR-ATR analysis, we estimated the average annual deposition of plastic and other debris by the wintering gull population into the lake.

Main results

86 % of pellets contained plastics, and 94 % contained other debris such as glass and textiles. Polyethylene (54 %), polypropylene (11.5 %) and polystyrene (11.5 %) were the main plastic polymers. An estimated annual mean of 400 kg of plastics were moved by gulls into the lake. Only 1 % of plastic mass was imported in faeces.

Discussion

Incorporating the biovectoring role of birds can provide a more holistic view of the plastic cycle and waste management. Biovectoring is predictable in sites worldwide where gulls and other waterbirds feed in landfills and roost in wetlands. We discuss bird deterrence and other ways of mitigating debris leakage into aquatic ecosystems.

For UK sites, this work was funded by the Department for Energy Security and Net Zero (DESNZ), through the Offshore Energy Strategic Environmental Assessment research programme, with the contract managed by John Hartley (Hartley Anderson Ltd), and was further funded by Ørsted, and supported by the Marine Renewable Energy and the Environment (MaREE) project (funded by Highlands and Islands Enterprise, the European Regional Development Fund and the Scottish Funding Council).

Arctic Skua migration: stories from the field

WEBSITEEDITOR — Fri, 13 Oct 2023 16:18:50 +0000

Where do Arctic Skuas go when they are not in Scotland? Helen and David Aiton take us through their fieldwork seasons for BTO’s Arctic Skua tracking project, which has followed these fascinating birds across both hemispheres and back. No

Helen and David Aiton

Helen and David Aiton have been members of BTO for over 40 years. Over this period, they have contributed to many BTO surveys and currently have a Breeding Bird Survey site on Rousay.

We were drawn to these beautiful birds by their plaintive calls, their stunning range of plumages and – sadly – their rapid population decline. In 1991, there were 122 pairs in our study area along with thousands of Arctic Terns. Now, in 2023, there are only 17 Arctic Skua pairs and a mere handful of breeding Arctic Terns. This trend reflects that of the UK breeding population more broadly, which is restricted to north and west Scotland and has declined by 70% since 2000.

Our fieldwork site is a triangular area of coastal moorland approximately 2 km by 1.5 km and varies from 5–115 m above sea level. We also research Great Skuas in our study area – but that is a story for another time! The aim of our long-term study is to monitor how both skua species are faring in these turbulent times.

This year, 2023, was the 10th season of our Arctic Skua productivity study, which measures the breeding success of the colony. We collect information about the number of eggs, chicks and fledged young every breeding season. Over the past 10 years, our colony has fledged 96 juvenile birds.

newly_hatched_arctic_skua_chick_still_with_an_egg_tooth.jpg

A newly hatched Arctic Skua chick with its ‘egg tooth’, a sharp point on its beak that helps the chick to break the eggshell from the inside when it is ready to hatch. The egg tooth falls off the beak around a day after hatching.

Fieldwork on Rousay

Each year we visit the study area at least eight times, an effort of 16 days minimum. The island can be reached by a 30-minute ferry trip, crossing the beautiful Eynhallow Sound. Our fieldwork is made more comfortable in our old VW Campervan for overnight stays.

We locate nests at the start of each breeding season from vantage points at least 200 metres away: one person remains at the vantage point and directs the other using radios, to as many as five nests at a time. Arctic Skua nests are well hidden, so we have to use sightlines and surrounding vegetation to memorise their positions, so we can monitor them throughout the season.

Arctic Skua nests are well hidden, so we have to use sightlines and surrounding vegetation to memorise their positions.

We also use our two highly-trained German Shorthaired Pointers to increase the efficiency of finding chicks which have become more mobile and might have wandered away from the nest. It’s very important that we only undertake nest and chick finding in dry, warm weather to avoid the risk of causing any harm due to chilling.

The Arctic Skua tracking project

helen_holding_a_dark-phase_bird_ready_for_release._the_orange_darvic_with_the_geolocator_attached_is_on_the_birds_left_leg.jpg

Helen holding an adult bird ready for release. The geolocator is attached to the uniquely-coded orange ring on the Arctic Skua’s left leg.

Liz Humphreys from BTO Scotland contacted us in 2018, having heard about our well-established study. BTO’s scientists were keen to use geolocators to track the adult Arctic Skuas, to find out where they spent their winters, and to learn more about their migration routes. This information would help inform conservation efforts to protect this species. The work on Rousay would build on the study of Fair Isle breeding Arctic Skuas, which BTO began in 2017, and offer a comparator site. Fair Isle is roughly 30 miles from Orkney.

BTO’s Senior Research Ecologist John Callandine joined us for a week on Rousay, arriving in late May 2018. Luckily for John, we had a week of hot, dry and still weather, almost unknown in Orkney – highly suitable conditions for checking nests and catching adult birds for tagging. He was delighted that we had already located the nesting birds.

Luckily, we had a week of hot, dry and still weather, almost unknown in Orkney – highly suitable conditions for checking nests and catching adult birds for tagging.

john_and_david_with_a_walk-in_trap_over_dummy_eggs_in_the_nest_cup._the_real_eggs_are_safely_stored_in_the_box_john_is_holding.jpg

John (left) and David (right) place a walk-in trap over dummy eggs in the nest cup. The real eggs are safely stored in the box John is holding.

For the tagging project, we chose mostly well-established pairs of adult birds. Over the next few days, we watched the birds and waited for them to lay a full clutch of eggs. We then prepared the walk-in traps – safe structures for catching the adult birds – and left them for a couple of days near the nests, to habituate the birds to them.

Eventually, we placed the traps over the nests, to catch the adults as they walked onto the nest to incubate the eggs. To keep the eggs safe from predators while we tagged the adults, we removed them temporarily and replaced them with dummy eggs before putting the walk-in trap over the nest.

John had honed the techniques for catching birds on Fair Isle the year before, so we were a slick team! We caught 10 individual birds, two of which were a pair. As soon as the tagging was finished we replaced the real eggs. The whole process never took more than an hour.

John then left Rousay to go to Fair Isle to catch more birds, and we continued our study for the rest of the summer. It was reassuring that the birds with geolocators continued to behave normally, with most of them rearing chicks successfully that year.

Collecting the geolocator data

pale_phase_arctic_skua_by_ondrej_prosicky_top_and_dark_phase_arctic_skua_by_maciej_jaroszewski_bottom.png

Arctic Skua plumage falls broadly into two ‘phases’: pale phase (as in the bird in the top photograph) and dark phase (as in the bird in the bottom photograph). Plumage which is intermediate between these phases can also occur in some birds.

Using geolocators as a tool to understand migration routes does not provide instant gratification. To collect the data from the geolocators, they have to be retrieved from the birds, which meant we had to catch the tagged birds again to get any information at all! Innocent of the wiles and intelligence of Arctic Skuas we returned to Rousay in late spring 2019, keenly anticipating retrieving the geolocators and continuing our productivity study.

John joined us again in early June to begin the retrieval process and repeat the procedure using the walk-in traps. However, of the 10 birds we caught in 2018, only eight birds had returned, and one of the birds that did return tried to breed, but her nest failed before we had a chance to try to recapture her with the walk-in traps – down to seven birds.

Arctic Skuas share incubation duties, with both the male and the female sitting on eggs. Because individual Arctic Skuas can occur in one of two plumage types – birds are either ‘dark’ or ‘pale’ phase – we could tell the male and female apart if they had different phase plumage, what we called a ‘dark-pale phase pair combination’. But for a dark-dark phase pair combination, where only one of the pair was carrying a geolocator, we had to take extra care to ensure we were catching the right bird.

The first bird we tried to catch, a female pale-phase bird, walked straight into the walk-in trap and onto the dummy eggs – hurrah – Geolocator Number 1. After this, we thought – this was going to be easy! Alas not. That was the only geolocator retrieved during John’s visit, despite trying for the remaining six birds who all refused to go back into a walk-in trap.

Later in June, we tried mist-netting one pair that had a young chick. A mist net is a fine mesh held taut between two vertical poles, which we can use to safely catch birds by encouraging them to fly or walk into it (in this case, by placing a stuffed predator close by to the net in the hope that the adult birds would fly into the net while mobbing it) but the adults very cleverly called the chick away from the net instead. Sigh!

We were fortunate that one pair – which had had a single egg predated by a neighbouring Arctic Skua (quite common in the skua colonies) – re-laid, and had a young chick less than a week old in late July. With both adults close to their nest, we had the opportunity to try recatching them, and this time both threw themselves into the mist net at the same time! Geolocator Number 2 retrieved.

As in 2018, the colony went on to successfully fledge chicks, including that late chick.

A brief hiatus ...

Due to COVID-19 restrictions in 2020, we were not able to return to Rousay until early July, by which time the chicks were too old for us to try to catch the adults with a mist net. Again, though, it was a good year for the Arctic Skuas and they fledged at least 10 chicks.

... before fieldwork resumed

john_and_david_relaxing_before_johns_ferry_to_mainland_orkney.jpg

John (left) and David (right) relaxing on the Rousay pier after fieldwork was complete.

In 2021, three years after putting the geolocators on the birds, John joined us again in glorious weather in early June. There were still four birds with geolocators breeding in the colony. We successfully mist-netted a female using dummy eggs and a stuffed predator, which she duly mobbed and entered the mist net – Geolocator Number 3 retrieved.

John and David worked very hard to retrieve the remaining three geolocators, but the birds refused to engage with the walk-in traps or the mist nets. Later in June, we tried again with the dark-phase male mate of the first pale-phase bird we retrapped in 2019 – and success! – he eventually walked into the trap and settled on the dummy eggs – Geolocator Number 4. We hoped at the very least that the birds we recaught to retrieve the geolocators this year would give us two years’ worth of migration information.

Finally, after approximately 200 hours of effort, we had four geolocators retrieved, along with six geolocators from John’s work on Fair Isle. The BTO team could set about retrieving the data from the geolocators and plotting the migration routes of the 10 Arctic Skuas. It is no exaggeration that we were all thrilled to see the results.

Migration stories revealed

rousay_skua_wintering_grounds.jpg

Circles show the different wintering locations of individual Arctic Skuas, each of which is represented by a different colour. Two circles of the same colour represent the wintering locations of the same bird in consecutive winters. Different birds from the same breeding colony spent our winter months off the coast of north-west Africa, south-west Africa, or the east coast of South America. The triangle shows the location of Rousay, Orkney, where the Arctic Skuas breed.

The data showed that all the Arctic Skuas travelled south via the North Sea and English Channel. Then down past France, Spain and Portugal to the coast of north-west Africa and on to their wintering grounds.

Individual Arctic Skuas wintered in different locations: off the coast of north-west Africa, the coast of south-west Africa or the east coast of South America. The accuracy of the data is roughly to the nearest 200 km so the birds are not actually on land, as can appear in the maps of the location points – they overwinter at sea. The birds that had data over two winters went back to the same area each year. Astonishingly, our pair of birds that both had geolocators went to different continents!

The work we did in Scotland will also be part of a multi-colony study of Arctic Skua wintering and migration movement involving colonies right across their north-east Atlantic breeding range – some of which was presented by BTO Senior Research Ecologist Nina O’Hanlon to the International Seabird Group Conference in Cork in September 2022 and has now been submitted for peer review. You can read more about the project’s findings in Nina’s blog.

It is rewarding to see the work we contributed to being part of a published international study. Even two years after the maps were produced, it is still deeply satisfying to be able to visualise the journeys of the Arctic Skuas when they are not on Rousay.

Since the Arctic Skua research programme was established in 2017, BTO donors have donated more than £225,000 to fund the work. We are enormously grateful for this very generous support from a small number of committed individuals. The research could not have been delivered without this funding. We would also like to thank the Scottish Ornithologists’ Club for annual grants that cover the cost of the productivity study on Rousay.

World Migratory Bird Day 2023

This blog post was created to celebrate World Migratory Bird Day (WMBD) 2023, a global event which increases the level of awareness about the threats that migratory birds are facing.

The theme of WMBD 2023 is Water, which highlights the importance of this resource for migrating birds – including for species like the Arctic Skua, which spends most of its life at sea and migrates thousands of kilometres over the ocean and across both hemispheres every year.

BTO’s Arctic Skua tracking project aims to understand where these birds spend their time when they’re not at their breeding colonies, so we can better inform global efforts to protect this species.

Discover more about Rousay’s Arctic Skuas and their astonishing migration in our other blog for WMBD 2023, written by BTO Senior Research Ecologist Nina O’Hanlon.

wmbd-2023-poster.jpg

Helen and David Aiton take us through their fieldwork seasons for BTO’s Arctic Skua tracking project.

1 October 2023

Where do Arctic Skuas go when they are not here?

For us, ‘here’ is Rousay, an island which lies off the West Mainland of Orkney. We have been measuring the breeding success of Arctic Skuas since 2014, and working with BTO to help track the adult birds’ migration since 2018.

13 Oct 2023

Scotland

Combining remote sensing and tracking data to quantify species’ cumulative exposure to anthropogenic change

VIOLA.ROSS-SMITH — Tue, 10 Oct 2023 09:15:21 +0000

The Cuckoo cohort of 2024 takes flight!

More Details

Buchan, C., Gilroy, J.J., Catry, I., Hewson, C.M., Atkinson, P.W. & Franco, A.M.A Global Change Biology 10.1111/gcb.16974 Identifying when and where organisms are exposed to anthropogenic change is crucial for diagnosing the drivers of biodiversity declines and implementing effective conservation measures. Accurately measuring individual-scale exposure to anthropogenic impacts across the annual cycle as they move across continents requires an approach that is both spatially and temporally explicit—now achievable through recent parallel advances in remote-sensing and individual tracking technologies. We combined 10 years of tracking data for a long-distance migrant, (common cuckoo, Cuculus canorus), with multi-dimensional remote-sensed spatial datasets encompassing thirteen relevant anthropogenic impacts (including infrastructure, hunting, habitat change, and climate change), to quantify mean hourly and total accumulated exposure of tracked individuals to anthropogenic change across each stage of the annual cycle. Although mean hourly exposure to anthropogenic change was greatest in the breeding stage, accumulated exposure to changes associated with direct mortality risks (e.g., built infrastructure) and with climate were greatest during the wintering stage, which comprised 63% of the annual cycle on average for tracked individuals. Exposure to anthropogenic change varied considerably within and between migratory flyways, but there were no clear between-flyway differences in overall exposure during migration stages. However, more easterly autumn migratory routes were significantly associated with lower subsequent exposure to anthropogenic impacts in the winter stage. Cumulative change exposure was not significantly associated with recent local-scale population trends in the breeding range, possibly because cuckoos from shared breeding areas may follow divergent migration routes and therefore encounter very different risk landscapes. Our study highlights the potential for the integration of tracking data and high-resolution remote sensing to generate valuable and detailed new insights into the impacts of environmental change on wild species. The BTO Cuckoo Tracking Project was funded by the A. G. Leventis Foundation, BBC Wildlife Fund, Dulverton Trust, BTO including from much appreciated gifts in Wills, Ernest Kleinwort Charitable Trust, Essex and Suffolk Water, Mark Constantine, Tobit Trust and ‘Cuckoo Sponsors and Champions’. The authors thank everyone who provided assistance in the field, Paul and Russell Howey for assistance with PTTs, and BTO Fundraising and Communications teams for vital contributions to the project. CB was funded by a PhD studentship from the Natural Environment Research Council, grant number NE/L002582/1. IC was funded by contract 2021.03224.CEECIND from FCT (Fundação para a Ciência e Tecnologia).

Cuckoos’ clocks can’t adjust to climate change – now we know why

WEBSITEEDITOR — Wed, 21 Jun 2023 14:46:17 +0000

Why aren’t Cuckoos returning any earlier as spring advances, and why is this important? No

Chris Hewson

Senior Research Ecologist

Chris is a Senior Research Ecologist in the Framing Futures Team where he works on the status, ecology and conservation of Afro-Palaearctic migratory birds and of forest birds across the world.

Projects primarily focus on improving knowledge of the migration ecology of these species, with the aim of understanding the drivers of recent population changes and the likely population impacts of projected environmental change, with the ultimate aim of facilitating restoration of flyways and populations.

Cuckoo Tracking Project

Science

Staff voices

The difference we make

UK springs are starting earlier as the climate warms, with bud burst and the emergence of invertebrates such as caterpillars that eat this young vegetation happening earlier too. These invertebrates are a vital and ephemeral food source for breeding birds, so migratory species that have not advanced their migrations and subsequent breeding accordingly risk missing out.

One species that has not significantly shifted the timing of its spring migration forward is the Cuckoo, the iconic harbinger of spring. Previous BTO work has shown that the advance in the Cuckoo’s arrival has been smaller than that of many other species, and it has undergone a substantial population decline, in England especially.

In general, both migratory and resident species that have not advanced their breeding have undergone greater population declines than others, but there’s been limited evidence linking this to a reduction in breeding success in these species. This suggests that other demographic pathways, such as adult survival, may be important. Understanding why some migratory species have not advanced their arrival, and what the consequences of this are outside of the breeding season, is therefore vital for understanding population declines and helping us work out the best ways to help.

Investigating the drivers of the Cuckoo’s migratory schedule

Satellite-tagged Cuckoo. Mike Toms / BTO

Using data from 87 adult male Cuckoos tagged as part of BTO’s Cuckoo Tracking Project, we looked at which events across their annual migratory schedule were most important in determining when birds arrived back to the breeding grounds. We also looked at whether migratory timing affected mortality risk at different migratory stages. And to help us understand variation in timing across the annual cycle, we examined whether timing was consistent between individuals.

We found that the timing of departure from the pre-Sahara crossing stopover in West Africa in spring is the most important factor in determining when Cuckoos arrive back to the UK. Furthermore, both the high level of synchrony across the population at this stage and relatively modest levels of consistent timing differences between individuals suggest that environmental conditions constrain when birds can depart from this stopover.

Our tracking work has revealed that Cuckoos use this stopover in March and April each year. In this part of Africa, rains arrive at this time every year, moving up from the southern hemisphere in association with a system known as the Intertropical Convergence Zone. These rains bring about a flush of invertebrate prey, which migratory species such as the Cuckoo rely on to fuel their northward journeys. This study is the first to find that departure from a stopover site limits a land bird species’ arrival to its breeding grounds across multiple years.

In addition to departure from West Africa, we found that spring arrival on the breeding grounds was determined to lesser, but important, extent by migration speed during the northward journey across Europe, as well as the timing of Cuckoos’ arrival south of the Sahara the previous autumn. The latter is surprising given that earlier research has shown timing differences between individuals are largely reset during the winter period – there is usually only a limited carry-over effect of timing from autumn to spring migration.

Why can’t Cuckoos change their clocks?

Previous research looking at patterns across many species has shown that, in general, the timing of departure from the wintering grounds is the major determinant of variation in when migratory birds arrive back to their breeding sites. The timing of this departure also has a higher level of consistent differences between individuals than other events. This indicates a greater direct control by internal migration programmes. Hence, an advance in the timing of departure from wintering sites provides a potential evolutionary mechanism via which spring arrival at breeding grounds can also be advanced.

Our results show, however, that this is not an option for UK Cuckoos. The timing of their departure from their wintering grounds in the Congo rainforest zone has little effect on when they arrive back to their breeding sites; in fact, all other things being equal, birds that depart their wintering grounds later arrive back a little earlier.

These results help us to understand both why the phenological response (the timing of annual cycle events) to climate change is so limited in some species, and why migratory species which travel further are less likely to be able to advance their spring arrival timing than ones that make shorter journeys. Similar results might be found for some other very long-distance migrants which, like the Cuckoo, migrate to the southern hemisphere for the midwinter period and rely on stopovers in the northern tropics to prepare for crossing the Sahara in spring. Overall, the seasonality of sites used across the annual cycle is likely to be more important than their position in the annual cycle in determining their relationship to breeding grounds arrival and the potential for its advance.

Why is it important to understand what drives birds’ migratory behaviour?

Cuckoos which arrive earlier in the UK to establish the best territories risk a higher level of mortality. Edmund Fellowes / BTO

By looking at how mortality risk varied with timing across the annual cycle, we were able to gain some important insights into how these limitations to migratory change can impact individual birds, and therefore potentially populations.

In periods following the migration stages that were most important in determining the timing of arrival on breeding grounds, early birds were more likely to die than later ones. This suggests that, to try to gain the benefits of early breeding grounds arrival, such as claiming the best breeding territories, birds suffer increased mortality risk. In other words, there is a trade-off between survival and the benefits of early arrival, perhaps due to birds migrating with less on-board fuel than they otherwise would. Such risks may become more necessary as birds try to keep up with climate change on the breeding grounds.

The fact that we found that migration timing didn’t reset during the midwinter period, and that part of post-breeding migration is included in the periods when birds appear to be exposing themselves to these risks, suggests that in the case of UK Cuckoos, all ecological levers are being pulled in an attempt to advance spring arrival. The resulting increased mortality may form part of the demographic mechanisms linking failure to advance spring arrival to population declines.

Using our research to help birds adapt to global change

Providing higher quality habitat at breeding grounds like Wheatfen, Norfolk will support Cuckoos. Phil Atkinson / BTO

Not only do these results help in understanding why some species are not keeping pace with ever earlier springs and advancing their arrival to the breeding grounds, and how this might impact their populations, it also helps to show how we might help these birds cope better with the demands of global change.

We can identify pinch points in the annual cycle that impact spring arrival, and where early birds are at increased risk of mortality. The stresses these birds are under can potentially be alleviated by improving habitat quality at stopovers, to increase fattening rates and reduce costly trade-offs between survival and reproduction. The most important places to concentrate flyway restoration efforts are the stopovers used in spring and autumn to prepare for the Sahara crossings and, to lesser extent, the areas used to recover from the Sahara crossings and migration across Europe in spring.

As we also found that birds that were late leaving the breeding grounds were at greater risk of dying than those leaving earlier, suggesting they are energetically limited at this point, provision of better-quality habitat on the breeding grounds is also a priority.

Cuckoos in our past and in our future

These results shed light on one of the oldest mysteries in folklore – what determines when Cuckoos arrive back at their breeding sites, and whether they really are a sign that spring is here...Ultimately, they could help us reverse the Cuckoo’s population decline in the UK.

These results shed light on one of the oldest mysteries in folklore – what determines when Cuckoos arrive back at their breeding sites and whether they really are a sign that spring is here. These results show that in fact, events occurring more than three thousand miles away are more important in determining overall variation in Cuckoo arrival back to the UK than events closer to home. But when focusing specifically on whether individual birds are early or late relative to their own schedule in different years, it seems that conditions in Europe are much more important. So, as Cuckoos are very faithful to their breeding sites, the old adage that Cuckoos are a sign that spring is on the way may well contain some truth from a local perspective after all.

In our future work, we will need to assess exactly how the departure of Cuckoos from critical stopover sites is impacted by the combination of climatic and habitat factors birds experience. This will give us a better idea of how each currently contributes to the timing and success of migrations, and how best we might use habitat restoration to help birds improve migratory performance, and ultimately, reverse their population declines in the UK.

2 June 2023 Can Cuckoos adapt their clocks to climate change?

Several studies from BTO and elsewhere have revealed alarming declines in species that breed in the UK and spend our winter months in Africa. However, these declines are less severe in migratory species that have adjusted the timing of their arrival back to their UK breeding grounds to keep pace with ever earlier northern hemisphere springs. But one species that has not significantly shifted the timing of its spring migration forward is the Cuckoo, the iconic harbinger of spring.

21 Jun 2023 no

2023’s Cuckoos are tagged and ready to go

WEBSITEEDITOR — Mon, 05 Jun 2023 14:57:23 +0000

07 Jun 2023

BTO has fitted 10 more Cuckoos with state-of-the-art satellite tags, continuing the long-running Cuckoo Tracking Project that allows scientists and the general public to follow these incredible birds on their annual migration to central Africa and back.

The UK’s breeding Cuckoos have declined by more than a third since the 1960s, with their iconic “cuck-oo” call slowly disappearing from much of our spring landscape. Ireland has also lost 27% of its Cuckoos since the early 1980s.

We still don’t have a full or nuanced understanding of what is causing these declines, and following Cuckoos on migration helps researchers understand the pressures they face outside the UK.

Skip to the Cuckoo tracking map

Every tagged Cuckoo provides us with invaluable data, improving our understanding of this extraordinary species and increasing the chances of developing effective conservation measures to reverse its fortunes.

Since it began in 2011, BTO's Cuckoo Tracking Project has tagged more than 100 Cuckoos. The work has revealed that many English Cuckoos migrate via Spain, a route associated with higher mortality than that through Italy, which is used by Scottish Cuckoos.

The differences in survival rates are linked to the conditions at sites in southern Europe, where Cuckoos stop to refuel and store up energy reserves for the remainder of their journey. The decreasing volume of large insect prey on the Cuckoos’ breeding grounds in the UK and Ireland may also impact their ability to successfully complete their migration.

A first for the tracking project: Cuckoos in Ireland

the-burren-lee-barber.jpg

The fine mist net which licensed researchers use to catch Cuckoos, set up in Burren National Park, Ireland. Lee Barber

This year, as part of a collaboration between BTO and Ireland’s National Parks & Wildlife Service, we have also tagged Cuckoos breeding in Ireland. This is an exciting first for the Cuckoo Tracking Project, and means that we will be able to see which route this population follows on their migration south for the very first time.

‘Cuach Cores’, ‘Cuach Torc’, and ‘KP’ were all caught and tagged near Incheens in Killarney National Park, County Kerry. The team from BTO and Ireland’s National Parks & Wildlife Service arrived at 4 a.m. to begin their morning, and were delighted to catch the three birds before the sun came up and the midges emerged.

The fourth Irish Cuckoo, ‘Cuach Carran’, was caught in Burren National Park, County Clare.

Unusually, it was clear from his plumage that Cuach Carran hatched only last year; most of the Cuckoos caught and tagged by our scientists can’t be aged this precisely. It will be interesting to see how this young Cuckoo fares on his migration.

It’s especially exciting to see birds from Ireland tagged – we’re looking forward to learning for the first time about the migrations of these Cuckoos, especially as they were found in the western extremity of the species’ breeding range. Chris Hewson, lead scientist on the Cuckoo Tracking Project

A surprise at Knepp: Bluey returns!

volunteer-abbie-and-chas-holt-extract-bluey.-lee-barber.jpg

Fieldworkers extract the ‘mystery’ Cuckoo from the mist net – before they discover the bird is Bluey. Lee Barber

In England, ‘Michael’ and ‘George’ were tagged at Loddon Common in the Norfolk Broads, ‘Jasper’ was tagged in King’s Forest, Suffolk and another Cuckoo, ‘Trent’, was tagged at Ryall, Worcestershire.

The fieldwork team got a surprise at Knepp, Sussex, when they caught a bird with an existing tag. Using the unique number stamped on the metal leg ring the bird was also sporting, the team identified the Cuckoo as ‘Bluey’ – a bird tagged last year, who was presumed to have died after his tag stopped transmitting data!

Bluey was fitted with a new tag, and we’re delighted to be able to follow him for a second year of migration journeys. A new bird, ‘Sayaan’, was also tagged, bringing the total number of Cuckoos to 10.

What’s next for the 2023 Cuckoos?

river_congo_kinshasa._catherine_stock_adobe_com.jpg

The Congo River in Kinshasa, Democratic Republic of the Congo. Famous BTO Cuckoo PJ spent winter of 2022/22 around 100 miles from the city. Catherine / adobe.stock.com

The Cuckoos will soon begin their epic journey south, heading towards central Africa. These stages of the birds’ lives are not for the faint-hearted.

After heading out across the English Channel and south through Europe, the Cuckoos have a Mediterranean Sea crossing to contend with before they face the Sahara, the biggest challenge of all. Most traverse the desert in a single non-stop flight, travelling at altitudes of up to 5 km to avoid the worst of the daytime heat.

Although not all of them survive their first migratory journey, every tagged Cuckoo provides us with invaluable data, improving our understanding of this extraordinary species and increasing the chances of developing effective conservation measures to reverse its fortunes.

Class of 2023

Follow this year's cohort on their migration to the Congo Basin and back.

class_of_2023_cuckoos.png

Sponsor a Cuckoo

Choose a Cuckoo to sponsor and support the future of this project.

What have we learnt?

cuckoo_sarah-kelman.jpg

Yes

Cuckoo Tracking Project

Landscape fires disproportionally affect areas of conservation priority but only under low moisture conditions

VIOLA.ROSS-SMITH — Mon, 15 May 2023 10:36:05 +0000

The Cuckoo cohort of 2024 takes flight!

More Details

Kirkland, M., Atkinson, P.W., Pearce-Higgins, J.W., De Jong, M., Dowling, T.P.F., Grummoe, D., Critchley, M. & Ashton-Butt, A. Science of The Total Environment 10.1016/j.scitotenv.2023.163849

Landscape fires are a natural component of the Earth System. However, they are of growing global concern due to climate change exacerbating their multiple impacts on biodiversity, ecosystems, carbon storage, human health, economies, and wider society. Temperate regions are predicted to be at greatest risk of increasing fire activity due to climate change, where fires can seriously impact important ecosystems for biodiversity and carbon storage, such as peatlands and forests. There is insufficient literature on the background prevalence, distribution, and drivers of fires in these regions, especially within Europe, to assess and mitigate their risks. Using a global database of fire patches based on the MODIS FireCCI51 product, we address this knowledge gap by quantifying the current prevalence and size of fires in Polesia, a 150,000 km² area comprising a mosaic of peatland, forest, and agricultural habitats in northern Ukraine and southern Belarus. Between 2001 and 2019, fires burned 31,062 km² of land, and were most frequent in spring and autumn. Although most fires started in agricultural land, fires disproportionately affected natural and semi-natural land cover types, particularly in protected areas. Over one fifth of protected land burned. Coniferous forests were the most common land cover type in protected areas, but fires mostly occurred in meadows, open peatlands (especially fen and transition mires), and native deciduous forests. These land cover types were highly susceptible to fires under low soil moisture conditions, but the risk of fire was low under average or higher soil moisture conditions. Restoring and maintaining natural hydrological regimes could be an effective nature-based solution to increase the resilience of fire-vulnerable ecosystems and support global biodiversity and carbon storage commitments under the United Nations Framework Conventions on Climate Change and Convention on Biological Diversity.

The authors acknowledge support from BTO and the Endangered Landscapes Programme (ELP). ELP is managed by the Cambridge Conservation Initiative and is funded by Arcadia, a charitable fund of LisbetRausing and Peter Baldwin. Thanks to Wentao Chen and Florent Mouillot of Le Centre National de la Recherche Scientifique. Their input was invaluable in the acquiring and preparation of the fire data. Thanks to Neil Wilyman and Susana Baena for their technical input.

How important is it to standardise the measured mass of shorebirds weighed at varying intervals after capture?

VIOLA.ROSS-SMITH — Mon, 17 Apr 2023 13:35:04 +0000

The Cuckoo cohort of 2024 takes flight!

More Details

Clark, J.A., Gillings, S., Clark, N.A., Cole, K.B., Breese, G., Woods, J.L., Bellman, H.A. & Robinson, R.A. Wader Study 10.18194/ws.00297 Shorebirds are often caught in large samples and kept in temporary captivity for differing lengths of time before being banded, measured, weighed and released. As birds in temporary captivity lose mass as they digest their food and void their guts, those weighed first may have a higher relative mass than those weighed last, which can affect the mean recorded mass of a large catch. We recorded multiple mass measurements of individual shorebirds of four species Red Knot Calidris canutus (mean mass 148 g), Ruddy Turnstone Arenaria interpres (135 g), Dunlin C. alpina (64 g) and Semipalmated Sandpiper C. pusilla (29 g), caught in a series of catches on Delaware Bay, USA during spring passage. We modelled the rate of mass loss to provide a correction factor allowing individuals to be compared across catches and the mean mass of all birds in different catches to be compared. As birds caught in cannon-nets are rarely measured until at least 30 minutes after capture, masses were predicted for this time, thus reducing the size of the correction required. Time since capture was the most important predictor of mass loss. The mean defecation rate (number of droppings per bird per minute) was closely related to mass loss. Correction of mass for a catch of 372 Red Knot changed the mean mass of the birds in the catch from 147.8 g to 151.0 g, a difference of 3.2 g or 2%, although this was not significantly different from zero. To compare mass between catches, or to estimate fitness for departure, researchers should consider whether mass should be corrected to a standard time, taking account of local conditions such as when the birds last fed, the time since capture at which the first birds are weighed, and the maximum time between first and last weighing. The authors thank all those involved in the catches in Delaware from which these data were gathered, and especially Dave Carter whose energy and enthusiasm established the work in Delaware. They would also like to thank Sarah Dawkins and Ian Henderson for their help with the mass loss samples. This work was funded by Delaware Department of Natural Resources and Environmental Control through a series of contracts over the years 2001–03.

BTO goes batty: how our Acoustic Pipeline project is contributing to bat conservation in some of Europe’s most threatened landscapes

WEBSITEEDITOR — Mon, 10 Oct 2022 16:12:25 +0000

How our Acoustic Pipeline project is contributing to bat conservation in Europe’s most threatened landscapes.

Yes

Stuart Newson

Senior Research Ecologist

Stuart Newson is a Senior Research Ecologist in the Data Science and Bioacoustics team, where he is mainly involved in survey design and analyses of data from large national citizen science surveys.

Acoustic Pipeline

What is passive acoustic monitoring?

With game-changing improvements in acoustic sensors, passive acoustic monitoring (PAM) has increased exponentially over the last few years. ‘Passive’ monitoring refers to surveys which don’t require researchers or volunteers to be out for the whole time in the field recording the species; rather, the monitoring involves setting up a recording device that automatically captures sound recordings, which can be analysed later using specially designed software.

PAM can be incredibly useful for monitoring biodiversity when species are hard to survey using traditional approaches - for example, if they are nocturnal, or live in inaccessible habitats or geographical areas. However, development in this field has not been without its challenges. In order for PAM to be an effective monitoring tool, it’s vital that the software and algorithms involved can identify species from sound as accurately and reliably as possible. However, because the sounds produced by animals are so diverse, varying within and between species, the task of ‘training’ algorithms to identify species can be very tricky. It’s made additionally challenging as the variation in signals for many species is poorly understood.

The BTO Acoustic Pipeline is the result of a decade of work at BTO focused on building machine-learning algorithms to automatically identify species across a range of species groups, from birds and bats to moths and small mammals. The focus on species identification means it’s an ideal tool to support the Endangered Landscapes Programme (ELP), which funds a suite of projects across Europe aiming to restore ecosystems and make them more resilient to environmental change. How are the two related? PAM is a great way to reveal which species are present in an area and to monitor population changes before, during and after restoration work, which is vital for deciding how best to manage a restoration site. This is particularly true at the landscape scale of the ELP projects, when PAM’s strengths for remote monitoring really come into their own.

Acoustic monitoring and spectrograms

A spectrogram is a visual representation of a bioacoustic signal: a sound's frequency (pitch) and amplitude (volume), and how these change over time. Some spectrogram 'fingerprints' are unique to a species, so can be used to identify which species made the sound.

Eagle-Owl. Magdalena Bujak / stock.adobe.com

Eurasian Eagle-Owls have been rediscovered in Portugal's Greater Côa Valley with the BTO Acoustic Pipeline. Magdalena Bujak / stock.adobe.com

The Acoustic Pipeline in action

Through the ELP, BTO has been supporting acoustic projects in countries as diverse as Scotland, Portugal, Romania and Georgia, where researchers have used sound recorders to sample nocturnal ‘soundscapes’ - the term used to describe all the biological and non-biological sounds of the night. These recorders can be set up to record the sounds produced by a range of animals - not only the calls of birds and small mammals, but also the sounds made by bats and even some insects.

These surveys have generated millions of recordings - an amazing dataset, but one far too large for a person to sift through manually. This is where the BTO Acoustic Pipeline comes in: cutting-edge algorithms which automatically identify species within the recordings, mining these large datasets to generate valuable new information about species and their activity within the restoration sites.

There have already been some fascinating results, such as the rediscovery of Eurasian Eagle-Owls in the Greater Côa Valley in Portugal. These owls hadn’t been detected in the valley for many years, and there were fears that a recently established Griffon Vulture colony might have displaced them. But when our colleagues at Rewilding Portugal sent us recordings from their passive acoustic monitoring in the valley, the Acoustic Pipeline’s bird classifiers were able to identify the calls of Eurasian Eagle-Owls within them.

This was particularly satisfying as detecting the owls did not mean resorting to 'playback' techniques, which use sound recordings to mimic an 'intruder' in a bird's territory. This elicits territorial calling from real birds in the area, allowing us to detect their presence. Responding to a territorial threat can be stressful, though, so avoiding playback techniques means we also avoided any unnecessary energy costs for these birds.

But discoveries are also being made for an even more elusive group of species: bats.

Bats are particularly difficult to monitor because most are nocturnal, wide-ranging and they can be difficult to identify.

BTO and bats: solving a cryptic puzzle

Lesser Mouse-eared Bats often form mixed colonies with other species including the Greater Mouse-eared Bat and the Cyptic Myotis. Ivan Kuzmin / stock.adobe.com

Over the past ten years, BTO has been developing knowledge and techniques to identify many of the 46 European bat species by sound. As a group, bats are particularly difficult to monitor because most are nocturnal, wide-ranging and can be difficult to identify. Potentially, the European bat species that need the most conservation and monitoring work now are some of the most poorly known and challenging species to study.

Funding from the ELP made it possible for us to hone in on some of these species. As a result, we have been able to conduct essential research into the calls of Lesser Mouse-eared Bat, Greater Mouse-eared Bat and the (appropriately named) Cryptic Myotis. Currently, there are no good criteria for distinguishing the calls of the Lesser Mouse-eared Bat from those of the closely related Greater Mouse-eared Bat, a task made even more difficult by the fact that these species also form mixed colonies. This means recordings from a colony will likely contain calls from several bats, with no way of knowing which call came from which species. Cryptic Myotis was overlooked completely until about ten years ago, when genetic work confirmed its existence as a species distinct from the closely related Natterer’s Bat.

To work on Cryptic Myotis and Lesser Mouse-eared Bat, we needed to collect many hundreds of recordings to capture the huge variation in calls that the bats produce. Bats use echolocation calls to navigate through their environment and find food, but also make social calls to communicate with each other as well as feeding ‘buzzes’, which are produced during the final moments of an attack on their prey.

Using spectrograms to distinguish bats

Spectrograms are useful for exploring differences in the calls between Greater Mouse-eared Bats, Lesser Mouse-eared Bats and Cryptic Myotis.

greater_mouse-eared_bat_spectrogram.png

Greater Mouse-eared Bat.

lesser_mouse-eared_bat_spectrogram.png

Lesser Mouse-eared Bat.

cryptic_myotis_spectrogram.png

Cryptic Myotis.

A juvenile Lesser Mouse-eared Bat from the hill fort colony. Fabrizio Gili

To gather these recordings, local knowledge and help are essential in making sure that recordings are from the target species, rather than any other species of bats that may be present at the same time.

In July, BTO’s Stuart Newson spent several days working with Fabrizio Gili from the University of Turin, and bat worker colleagues Elena Patriarca and Paolo Debernardi.

The team used harp traps to safely catch and identify bats from a 9th-century hill fort colony known to be home to over 600 Lesser Mouse-eared Bats and a smaller number of Cryptic Myotis.

Identifying the bats in the hand confirmed that it was unlikely that Greater Mouse-eared Bats were present in the colony, meaning that the team could be reasonably confident that any calls recorded would belong to either Lesser Mouse-eared Bat or Cryptic Myotis.

Foraging habitat around the 9th Century hill fort, Verrua Savoia (Piedmont, Italy). Fabrizio Gili

Static bat detectors set up along the bats' flight paths collected recordings as the bats exited the roost. Fabrizio Gili

The team set up static bat detectors along routes the bats were likely to use when entering or exiting the roost, to collect recordings of free-flying Lesser Mouse-eared Bats which could later be used to train algorithms how to distinguish this species from the Greater Mouse-eared Bat.

A month later, we updated the BTO Acoustic Pipeline algorithms to include the new sound data for Lesser Mouse-eared Bat and Cryptic Myotis. The Pipeline can now start to identify these species, making it possible for future ELP projects to monitor how their restoration activities might be helping these threatened species recover in degraded habitats.

Thanks to the ELP work and help from folk in Italy and Greece, there are now just six priority bat species in Europe still requiring sound identification research (excluding a small number of island endemics) - but these, of course, remain some of the most challenging.

There are still cryptic puzzles to solve.

The work described in this blog was undertaken by Stuart Newson (BTO) in collaboration with Fabrizio Gili (University of Turin), and Elena Patriarca and Paolo Debernardi. It was supported by the Endangered Landscapes Programme, and managed by the Cambridge Conservation Initiative in partnership with Arcadia, a charitable fund of Lisbet Rausing and Peter Baldwin.

The BTO Acoustic Pipeline

brings cutting-edge sound identification software to users' desktops, and is used in several key bioacoustic monitoring projects. Photo: Paul Colley

Learn more and get involved

1 October 2022 BTO goes batty BTO Acoustic PipelineBailiwick Bat Survey: 2021 Report

What happens when a landscape restoration programme and an innovative sound analysis project come together? Supported by the Endangered Landscapes Programme, scientists using the BTO Acoustic Pipeline to support biodiversity monitoring are making some amazing discoveries - and solving some cryptic puzzles.

Data Science and Bioacoustics Team

10 Oct 2022 no

Connectivity between countries established by landbirds and raptors migrating along the African-Eurasian flyway

VIOLA.ROSS-SMITH — Wed, 28 Sep 2022 09:27:45 +0000

The Cuckoo cohort of 2024 takes flight!

More Details

Guilherme, J.L., Jones, V.R., Catry, I., Beal, M., Dias, M.P., Oppel, S., Vickery, J.A., Hewson, C.M., Butchart, S.H.M. & Rodrigues, A.S.L. Conservation Biology 10.1111/cobi.14002 The conservation of long-distance migratory birds requires coordination between the multiple countries connected by the movements of these species. The recent expansion of tracking studies is shedding new light on these movements, but much of this information is fragmented and inaccessible to conservation practitioners and policy decision-makers. Here, we synthesize current knowledge on the connectivity established between countries by landbirds and raptors migrating along the African-Eurasian flyway. We reviewed tracking studies to compile migration records for 1,229 individual birds, from which we derived 544 migratory links, each link corresponding to a species’ connection between a breeding country in Europe and a non-breeding country in sub-Saharan Africa. We used these migratory links to analyse trends in knowledge over time, as well as spatial patterns of connectivity per country (across species), per species (across countries) and at the flyway scale (across all countries and all species). We found the taxonomic coverage of existing tracking data to be highly incomplete, with, to date, an average of just 7.5% of migratory landbird species and 14.6% of raptor species tracked per country. Furthermore, existing data are biased towards more westerly countries and larger bodied species. Despite these limitations, existing data can already inform conservation efforts, and we provide species- and country-level syntheses of the migratory links we identified (involving 123 populations of 43 species, migrating between 28 European and 43 African countries). Finally, we highlight countries (e.g., Spain, Poland, Ethiopia, Democratic Republic of Congo) that are strategic priorities for future tracking studies to complement existing data, particularly on landbirds. Our data and analyses can inform discussions under two key policy instruments at the flyway scale: the African-Eurasian Migratory Landbirds Action Plan, and the Memorandum of Understanding on the Conservation of Migratory Birds of Prey in Africa and Eurasia. The authors thank all scientists, conservationists and enthusiasts for their persistence and long field hours involved in capturing and tracking the birds whose migration records we used to estimate migratory links, and all experts from EU Member States that contributed to the official reporting under Article 12 of the EU's Birds Directive (2013-2018) and those from European countries and territories outside the EU, who provided data for the European Red List of Birds 2021. This study has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 766417. IC was supported by Fundação para a Ciência e Tecnologia (FCT) contract DL57/2016/CP1440/CT0023.

Spatial consistency in drivers of population dynamics of a declining migratory bird

WEBSITEEDITOR — Thu, 25 Aug 2022 11:57:40 +0000

The Cuckoo cohort of 2024 takes flight!

More Details

Nater, C.R., Burgess, M.D., Coffey, P., Harris, B., Lander, F., Price, D., Reed, M. & Robinson, R.A. Journal of Animal Ecology 10.1111/1365-2656.13834

1. Many migratory species are in decline across their geographical ranges. Single-population studies can provide important insights into drivers at a local scale, but effective conservation requires multi-population perspectives. This is challenging because relevant data are often hard to consolidate, and state-of-the-art analytical tools are typically tailored to specific datasets.

2. We capitalized on a recent data harmonization initiative (SPI-Birds) and linked it to a generalized modelling framework to identify the demographic and environmental drivers of large-scale population decline in migratory pied flycatchers (Ficedula hypoleuca) breeding across Britain.

3. We implemented a generalized integrated population model (IPM) to estimate age-specific vital rates, including their dependency on environmental conditions, and total and breeding population size of pied flycatchers using long-term (34–64 years) monitoring data from seven locations representative of the British breeding range. We then quantified the relative contributions of different vital rates and population structure to changes in short- and long-term population growth rate using transient life table response experiments (LTREs).

4. Substantial covariation in population sizes across breeding locations suggested that change was the result of large-scale drivers. This was supported by LTRE analyses, which attributed past changes in short-term population growth rates and long-term population trends primarily to variation in annual survival and dispersal dynamics, which largely act during migration and/or nonbreeding season. Contributions of variation in local reproductive parameters were small in comparison, despite sensitivity to local temperature and rainfall within the breeding period.

5. We show that both short- and long-term population changes of British breeding pied flycatchers are likely linked to factors acting during migration and in nonbreeding areas, where future research should be prioritized. We illustrate the potential of multi-population analyses for informing management at (inter)national scales and highlight the importance of data standardization, generalized and accessible analytical tools, and reproducible workflows to achieve them.

The authors are grateful to the many monitors from PiedFly.Net that have contributed to bird data collection. They thank the late Henry Robb and Gordon Vaughn for collecting the Loch Katrine data and most of the Okehampton data, respectively, and Irene Benedicto and Brian Sharkey for help with digitisation. Nestbox monitoring would not have been possible without the support of local landowners including Natural England, Woodland Trust, National Trust, and the Forestry Commission. They also thank Dave Koons and Matthieu Paquet for constructive discussions regarding methodology. This work was funded by the RSPB and the Research Council of Norway (#267511).

Latitudinal variation in arrival and breeding phenology of the pied flycatcher <em>Ficedula hypoleuca</em> using large-scale citizen science data

Many migratory birds are in decline. Efforts to tackle these declines are hampered by the fact that migratory species occupy different sites (e.g. breeding grounds, stopovers on migration) at different points in their annual cycle. They may also be hampered by differences in the factors driving the declines, with some operating on one part of the population and others exerting their effects on another; additionally, the impacts affecting individuals in one area can carryover to other areas. A particular challenge has been availability of the data needed to tease out what is happening at the wider spatial scales at which migratory populations exist and operate. Can a network of volunteers, working on the same species in different parts of its breeding range, help address this knowledge gap?

Like many other Afro-Palearctic migrants, Pied Flycatcher populations have decreased substantially over recent decades: 29% since 1980 across Europe and 43% since 1995 in the UK. Despite local declines being linked to climatic factors and weather effects in both breeding and non-breeding areas, understanding of the drivers of the large-scale decline in this species remains elusive.

By using the information collected by volunteer bird ringers working on seven UK Pied Flycatcher populations, and largely coordinated through the piedfly.net project, the research team behind this study was able to explore the demographic and environmental drivers of large-scale population decline here in the UK. The analyses revealed that the changes seen in Pied Flycatcher populations across the UK were most likely linked to factors acting during migration and in the non-breeding areas, rather than to changes in breeding success here in the UK. The influence of variation in local reproductive parameters (e.g. the number of eggs or chicks produced) on the observed population change was small, despite these breeding populations being sensitive to local temperature and rainfall within the breeding period. The seven populations tended to be more similar in trend than might have been expected, suggesting larger-scale changes, such as to survival during the non-breeding period were more important. This indicates that we should concentrate future research effort on what is happening to these birds during migration and on their wintering grounds, which could ultimately improve the fortunes of this declining species.