Author Archives: Glyn Young

Chough report: February 2013

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Report from Liz Corry

Captive choughs at Durrell

A chough receives its radio transmitter. Photo by Liz CorryWith the breeding season looming, staff at Durrell have been working hard this month to set up the breeding aviaries and move the birds around accordingly. Gianna was moved out of her off-show holding into the main display aviary. She was kept in the shut-off for two days as a way of re-introducing her to the group. She received a very uneventful welcome: Gwinny was the only one to fly down to her and that was only because she was looking for food.

Preparing the tail feathers for transmitter attachment. Photo by Liz CorryOn the 19th the three juveniles in SF3 were caught up and moved to the display aviary. These three birds will make up half of the release cohort. Before being released into the main flight all three birds were fitted with active radio-transmitters and an incoloy leg ring. The battery life on the radio transmitters is such that it should not run out before the birds moult tail feathers in autumn.

When the three juveniles were released into the main flight the other juveniles paid them a lot of attention. There was a lot of squabbling and defending of roost sites but no real aggression observed. The breeding pairs have stayed together throughout this which is looking positive for the new breeding season.

Tail mounted transmitter. Photo by Liz CorryOnce the juveniles had been moved out of the off show aviaries work could begin to prepare them for the breeding season. Apart from the obvious spring clean a few modifications were needed to improve our chances of a successful breeding season. Plywood has been added to a part of SF3 aviary to ensure a complete visual barrier between the choughs and any disturbance at the back of the aviary. The Orang-utan House kitchen and maintenance area is located behind the aviaries as well as other breeding bird enclosures. Daily disturbance should now be limited.

The nest box in SF2 has been relocated to the other side of the aviary to increase the distance between the two nests. We are not sure how much this influenced last year’s breeding, but the two pairs were very aware of each other and were almost synchronous in nesting behaviour, for example they kicked eggs out of the nest on the same days.

Another major difference compared to last season is in how we house the nest box cameras and what type of camera is used. We have tried to ensure the birds cannot tamper with the position of the lens. We are using different cameras and will not really know how effective they are until the birds are in the enclosure. No pun intended, but we will monitor closely!

Progress of the release aviary

Progress at the release aviary, late February. Photo by Liz CorryThe release aviary is now nearing completion. The major building tasks have been completed and the focus now is on making sure that the release hatches operate smoothly and all the necessary interior fixtures and fittings are in place. Work will begin on signage for the site when the choughs move into the aviary.

There were several visitors to the aviary in February including Mike Stentiford, Professor Carl Jones, Dr Richard Young and Paul Buckley. Each guest was shown around the aviary and went away suitably impressed.Visitors to the aviary, February 2013. Photo by Liz Corry

Other news

On the 10th, Sally Dalman from the National Trust for Jersey volunteered her time to shadow Liz for half a day in the Bird department. Unfortunately she picked a day where it persistently tipped it down with rain. However, it was still beneficial and both parties gained a greater understanding of what each other’s jobs involve.Progress at the release aviary, late February. Photo by Liz Corry

On the 23rd a group of Durrell’s volunteer guides were shown around the chough enclosures and updated on the progress of the release project and BOTE. They will hopefully be able to incorporate this information into their talks at the Wildlife Park and answer any questions posed by the public.

Biannual faecal samples were required from all the birds at Durrell this month; awaiting final results for choughs.

 

 

New study finds pesticides leading cause of grassland bird declines

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From American Bird Conservancy

Meadow pipit. Photo by Paul Marshall A new study in North America has identified acutely toxic pesticides as the most likely leading cause of the widespread decline in grassland bird numbers in the United States, a finding that challenges the widely-held assumption that loss of habitat is the primary cause of those population declines. Download the study for free here

Although this study focusses on the situation in North America it does state that: Common agricultural birds are in decline, both in Europe and in North America. Evidence from Europe suggests that agricultural intensification and, for some species, the indirect effects of pesticides mediated through a loss of insect food resource is in part responsible (for declines).

The scientific assessment, which looked at data over a 23-year period (1980 to 2003) has just been published. The study looked at five potential causes of grassland bird declines besides lethal pesticide risk: change in cropped pasture such as hay or alfalfa production, farming intensity or the proportion of agricultural land that is actively cropped, herbicide use, overall insecticide use, and change in permanent pasture and rangeland.

Common cuckoo juvenile. Photo by Mick Dryden“What this study suggests is that we need to start paying a lot more attention to the use of pesticides if we want to reverse, halt or simply slow the very significant downward trend in grassland bird populations. Our study put the spotlight on acutely toxic insecticides used in our cropland starting after the Second World War and persisting to this day – albeit at a lower level. The data suggest that loss of birds in agricultural fields is more than an unfortunate consequence of pest control; it may drive bird populations to local extinction,” co-author Pierre Mineau said.

Many grassland bird species have undergone range contractions or population declines in recent decades. In fact, analyses of North American birds indicate that these birds are declining faster than birds from other biomes (a situation mirrored in Europe). Habitat protection has long been considered a central pillar in efforts to stem the decline of grassland bird species.

“We are still concerned about loss of habitat in agriculture, range management, and urban development,” said Cynthia Palmer, manager of the Pesticides Programme at American Bird Conservancy. “This study by no means diminishes the importance of habitat fragmentation and degradation. But it suggests that we also need to rein in the use of lethal pesticides in agriculture, and that we need to be especially careful about any new pesticides we introduce into these ecosystems such as the neonicotinoid insecticides. It reminds us that the poisonings of birds and other wildlife chronicled a half century ago by famed biologist and author Rachel Carson are by no means a thing of the past.”

The study found that lethal pesticides were nearly four times more likely to be associated with population declines than the next most likely contributor, changes in cropped pasture – an important component of habitat loss associated with agricultural lands. The publication says that “…..large quantities of products of very high toxicity to birds have been used for decades despite evidence that poisonings were frequent even when products were applied according to label directions.”

The authors argue that only a small proportion of total cropland needs to be treated with a dangerous pesticide to affect overall bird population trends. Pesticide drift from croplands is also affecting birds that favour the adjoining grasslands.

The study found that declines of grassland birds were much more likely in states with high use of toxic insecticides lethal to birds. The current study relies on pesticide data from the 1980s and early 1990s, a time when organophosphates such as Diazinon and Chlorpyrifos, and carbamates such as Carbofuran and Methomyl, were still largely in vogue. Since that time, a new class of insecticides, the neonicotinoids, have soared to the top of global pesticide markets. Unfortunately, a major toxicological assessment soon to be released by American Bird Conservancy puts to rest any notion that birds and other organisms will fare much better under the new pesticide regime. Neonicotinoids have also been implicated in declines of bees – see the latest RSPB statement on use of these pesticides here

4th International Workshop on the Conservation of the Red-billed Chough

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4th International Chough Workshop. Photo by www.diogocarvalho.ptFrom Projecto Bico-vermelho (Pyrrhocorax Project)

Red-billed choughs in Barroso, Northern Portugal. Photo by Diogo Carvalho www.diogocarvalho.ptSince the first International chough workshop (Choughs and Land Use in Europe) in 1988 there have been regular meetings to discuss all aspects related to the biology, ecology and conservation of the red-billed chough (Pyrrhocorax pyrrhocorax). The species is a valuable indicator of sustainable agricultural systems and the connection to traditional farming methods. The red-billed chough is a species with an unfavourable conservation status on a global level, being listed as endangered in several countries including Portugal. In this context, after the 2007 and 2010 International Chough Workshops (in Glasgow and La Palma, respectively), Vila Real (North Portugal) is playing host to the 4th International Chough workshop on 10-12 October 2013. Two days of workshop will be followed by a day’s excursion.

As underlined in previous meetings, there is still a priority for chough research to understand the influence of the land-use/land-cover trends on the species’ distribution, taking into account on-going landscape changes, genetic diversity, fragmentation and isolation of peripheral populations. At these meetings all specialists agreed to further advance knowledge on the chough populations outside Europe, such as those in Asia and Africa, due to their particular threats and conservation requirements.

Although a considerable amount of information has been compiled and discussed at previous workshops about the chough ecology, all colleagues that are interested in choughs are invited to participate and share their expertise in the 4th International Workshop on the Conservation of the Chough.

The Workshop will be held at the University of Trás-os-Montes and Alto Douro (UTAD) in Vila Real, northern Portugal. Everyone interested in attending should  complete the automated registration form to confirm your participation. The submission deadline for contributions is 31 May, 2013. The organisers look forward to hearing from you.

Read more and register here

Choughs on Sept Îles – February 2013

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Choughs on 7 îles 2013. Photo copyright IGN Choughs on Ile aux Moines 2013. Photo copyright IGN Our Sept Îles correspondent Regis Perdriat from the LPO Station at Île Grande in Brittany reports that the choughs are still out on the islands. The last 3-4  surveys, have seen the choughs feeding on the same islet (the circle on the photos). The red spots show some of the places where the three birds were found before now. The choughs were even observed to chase away a raven that came around to Choughs on Bono 2013. Photo copyright IGN have a look.

The single, unringed, chough that visited Lundy Island in the UK’s Bristol Channel is still present on that island too. Read updates here

 

Chough report: January 2013

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Report from Liz Corry

Captive choughs at Durrell

Gianna. Photo by Fiona MarchantGianna continued visiting the vets at the start of the year to have her bandage changed until the 9th when it was removed. Another x-ray showed improvement, but she was put on a five-day course of anti-inflammatory pain killers as a precaution. It took her some time to get used to not having the ball bandage on and to realise she could use her foot again.

Gianna was caught up and moved to an off-show enclosure (X1B) on the 11th so we could provide her with more flight space whilst her condition improved. She weighed 275g on moving her.

Juvenile and breeding pairs in display aviary January 2013. Photo by Liz CorryOn the 26th we moved the three juveniles not marked for release up to the display aviary. They were kept in the shut-off area for two days before being released to allow them to acclimatise to the new surroundings and for the breeding pairs to get used to them. Typically, upon release, Tristan and Issy were the first ones to swoop down and check out the new arrivals. Arthur and Gwinny showed some interest, but on the whole left them alone.

B6977 with incoloy rings. Photo by Liz CorryThe three juveniles are the birds we have been testing with dummy radio tags and incoloy gull rings. We fitted B6976 ♂ with an incoloy ring using a new pair of ringing pliers specially adapted for the job. Thanks go to our Maintenance Department volunteer for his impressive metal work skills. There seems to be no further damage to the dummy tags or birds and no abrasions etc from the ring. All positive signs for the release birds.

Chough box with camera. Photo by Liz CorryWork began on fitting nest-box cameras at the end of the month. We will be using a different type of camera this year with a much better resolution. The camera is a different size and style so the existing nest-boxes have had to be modified. This year we have worked on making them tamper proof so the parents can’t move the lens off the nest. However, these cameras have a lot more infra-red lights on them (improving dusk/dawn image quality) which Chough box with camera. Photo by Liz Corrycould create a distraction or the birds could ignore them completely. Either way we will be watching closely to see how the birds behave in the box. If we think the new cameras are not working out we will have to modify.

Progress of the release aviary

Work on the release aviary started again after the winter festivities. Aaron kindly loaned us his lockable trailer once again so materials could be stored on site. The shed end is looking more like a shed and the netting is finally on the polytunnel.

Progress on release aviary. January 2013. Photo by Liz CorryHowever, yet again Trevor and his team had to battle the elements and the day snow came to Jersey was the day they finally had to down tools. One ongoing issue is the strong winds which puts a stop to any work involving a ladder. The other growing worry was that the snow and non-stop rain have completely saturated the fields and the truck was starting to churn up the ground beyond repair.

Once these issues can be resolved work will continue, but it now means that the completion date will be nearer the end of February. On the plus side it has freed up Trevor to come back to the Wildlife Park and fit the new nest box cameras.

 

Winter feeding: birds need a balanced diet too

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From the BTO

Blue tit. Photo by Mick DrydenAlthough many of us provide food for garden birds, especially in winter, we are still in the early stages of understanding how this might affect wild bird populations. One possibility is that winter food enhances birds’ ability to invest in future reproduction. However, it is likely that the exact nutrition a bird receives from supplementary food will be important and a new study has shown exactly that.

In a three year study of woodland blue tit populations, researchers examined the consequences of providing different winter food supplements for egg production. Their results showed that providing fat alone resulted in reduced egg quality in early breeders. This suggests that females which utilised a fat-rich diet in winter were less able to acquire some of the important resources needed to form yolk during egg production. However, the addition of vitamin E to the fat mitigated these affects because, as an antioxidant, vitamin E provides protection after eating fatty foods.

As urban land cover expands, gardens are expected to play an increasingly important role in the conservation of biodiversity. The provision of food for garden birds has been thought likely to benefit this objective although there is limited evidence of its ecological impacts. More generally, food provision has also been applied as a conservation tool to manage endangered populations. This study is the first to suggest that there may be problems. Yet at the population level, these were mitigated by the provision of fat together with vitamin E. Therefore, care must be given to the nutritional composition of foods. Whether winter food for garden birds is considered to be beneficial or harmful may depend on whether effects are interpreted at the level of individuals or populations. If provisioning enables certain low-quality individuals to breed, when they might otherwise have died or survived only as non-breeders, this would clearly enhance their lifetime reproduction and may in fact boost the overall population size. Further work is needed to see how winter feeding may be used to benefit wild bird populations in the future.

These findings suggest that birds require a balanced diet, much like we do, to aid their reproduction, and it underlines the importance of considering the nutritional value of provisioned foods.

Read the abstract from the study here

Population estimates of birds in Great Britain and the United Kingdom

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From British Birds

Wren. Photo by Mick DrydenThe journal British Birds has published an updated estimate of bird populations in Great Britain and the UK. This follows previous estimates published in 1997 and 2006. There are now thought to be about 84 million breeding pairs of birds in the UK. The ten commonest species contribute 57% of this total, with wren alone providing one in ten of the country’s breeding birds (with 8,600,000 breeding territories). In all, 23 species exceed one million breeding pairs. The individual population estimates come from a wide variety of sources, many from extrapolation of previous estimates by recognised trend measures, others from new surveys and novel analytical approaches developed since the last report. Despite the exceptional level of detail available for some species, many gaps in our knowledge remain. Recommendations are made in the report to allow a continuing improvement in our understanding of the numbers of birds in GB and the UK. There are many opportunities for volunteer and amateur birdwatchers to make a significant contribution.

Atlantic puffin. Photo by Paul MarshallAlthough the figures do not include birds from the Channel Islands the species that BIRDS ON THE EDGE are concerned with are in the list (2006 figures are in brackets):

  • Peregrine 1,500 pairs in UK and Isle of Man (1,283)
  • Atlantic puffin 580,000 breeding pairs (580,799)
  • Turtle dove 14,000 breeding territories (44,000)
  • Cuckoo 16,000 breeding pairs (9,600-20,000)
  • Red-billed chough 930-940 individuals in UK and 450 individuals in Isle of Man (total 1,360-1,367)
  • Raven 7,400 pairs (12,900)
  • Skylark 1,500,000 breeding territories (1,785,000)
  • Common whitethroat 1,100,000 breeding territories (945,000)
  • Dartford warbler 3,200 breeding pairs (1,600-1,890)
  • Stonechat 59,000 breeding pairs (9,000-23,000)
  • Meadow pipit 2,000,000 breeding pairs (1,600,00)
  • Linnet 430,000 breeding pairs (556,000)
  • Yellowhammer 710,000 breeding territories (792,000)
  • Cirl bunting 860 breeding territories (697)

Also of note are the recent colonists and other successes:

  • Little egret 660-740 breeding pairs (146-162)
  • Marsh harrier 320-380 breeding pairs (201)
  • Firecrest 550 breeding territories (80-250).

Jersey’s Great Garden Bird Watch

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The 12th Great Garden Bird Watch takes place this weekend, Saturday 2nd and Sunday 3rd February

Chaffinch. Photo by Mick DrydenIslanders are urged to become involved in monitoring bird life in the Island. The event is coordinated by Action for Wildlife Jersey in conjunction with the Jersey Evening Post (JEP) and all data received will be passed on to La Société Jersiaise to add to their records and included in BIRDS ON THE EDGE bird monitoring analyses. Data from past years’ surveys were included in the 2011 assessment of our birds that became the Island’s first bird redlist The Conservation Status of Jersey’s Birds which can be downloaded here.

How to enter the survey

Collared dove. Photo by Mick DrydenWatch the birds in your garden for any period between
8 am and 11 am on either the Saturday or the Sunday. Note the highest number of each species of bird that you see together at one time during that period – not the total number which enter your garden over the period of the watch. Survey forms and a handy identification guide will be published in the JEP on Thursday the 31st.

Completed forms can be posted in or delivered to the JEP or there is a convenient form for submitting records on line here.

Isles of Scilly rats to be removed to protect birds

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From This is Cornwall

Brown rat. Photo by Mark HowsTwo populations of an animal which thrives on two UK islands are to be removed. These are populations of invasive brown rats which are accused of threatening the future of several species of locally rare seabirds.

The human inhabitants on one of the islands, St Agnes, have been consulted and they have given a unanimous go-ahead for the rat clearance on their remote homeland and the neighbouring isle of Gugh.

European storm petrel. Photo by Mick DrydenThe Scillonian archipelago plays host to breeding populations of 14 seabird species (approximately 20,000 birds) but for years one of the major threats to the mainly ground-nesting birds has been rat predation of eggs and chicks. England’s only colony of storm petrels is said to be at risk from the rats, as is the local population of Manx shearwaters – for which the UK has a global responsibility.

The project aims to protect and restore the seabird population on the islands, which declined by almost a quarter between 1983 and 2006. Such birds are far outnumbered today by the brown rats which, according to a feasibility study, have a total Scillonian population of more than 34,500. Around 3,100 rats reside on St Agnes and Gugh, which happen to be close to the seabird breeding isle of Annet.

Julie Love, of the Isles of Scilly Trust said that “the feasibility study showed that rats can swim across from St Agnes and Gugh to Annet,”, “they eat both the eggs and the fledglings – in fact rats are even known to eat the rare Scilly shrew.”

David Mawer, the Isles of Scilly Trust senior conservation warden, added: “Seabirds already attract visitors to Scilly, and this project and the clever use of technology can reveal more of their fascinating lives, whilst leaving the seabirds free from unwanted disturbance.”

The rat-removal operation will take place in winter months and use special bait stations to prevent poisoning of non-target species.

Tony Whitehead, of the RSPB which is involved in the project, said “It is worth bearing in mind that it’s ten years this year since we removed rats from Lundy – with a resultant increase in seabird numbers. The Manx shearwater numbers there are now up by 250%”.

“This is part of a global push to restore island seabird populations from the teeth of invasive species,” he added.

Read more on the Isles of Scilly Seabird Recovery Project read here and details on the rat eradication here

For a detailed account of the rat eradication programme on Lundy Island dowload Conservation Evidence paper here

Jersey welcomes visitors. Lots of them!

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Winter lapwing in Jersey, January 2013. Photo by Paul MarshallThe current cold spell in north-west Europe will have been accompanied by the usual media activity in many places. Much of the news generated will focus on the regular “why weren’t we better  prepared” headlines. One group, however, that know exactly what to do when snow comes in the area are the many thousands of birds that winter in the region. While resident birds not used to such cold weather might have to make do, those species that have come from further north are quick to up and move until they find something more suitable. The most obvious places for these versatile wanderers to head for are the coast and offshore islands that are usually much milder than inland areas. And so, with the snowfall on Friday, Jersey welcomed many thousands of new arrivals.

Winter redwing in Jersey, January 2013. Photo by Paul MarshallThe usual clue to a cold-weather migration of this sort is the presence of lapwings on verges and every small field. While big flocks might develop in areas like the fields around St Ouen’s Pond, lapwings may happily feed alone in much smaller areas. The 2-300 lapwings on the Island on Thursday had been joined by possibly over a thousand more by Friday. Several small flocks of golden plovers came in with the lapwings – these two birds often join together in winter.

Winter fieldfare in Jersey, January 2013. Photo by Paul MarshallThe other abundant and obvious visitors are the thrushes. There were already plenty of wintering redwings on the Island but on Friday morning they were joined by many thousands more that had arrived across the parishes in fields and gardens alike.  New blackbirds and song thrushes had arrived too and were obvious as they tried to feed on the roadside at first light. Fieldfares, a bird formerly more common in the Jersey winter when winters were much colder than now, had also come in but only in smaller numbers so far. Interestingly, there are many less waterbird arrivals like ducks and grebes suggesting that so far it is only snow on the fields moving the wanderers and not the kind of cold temperatures that freeze ducks out of their ponds.