Songbird dads vary their 'catering' duties according to circumstances

Inexperienced females incubating eggs are fed more often by their partners, study finds

Date: July 6, 2016

Source: Springer

Expecting songbird dads do not always work themselves into frenzy to provide food to their partners sitting on the nest. They take breaks on warmer days, when food is more readily available or if their partner is older and more experienced in successfully hatching eggs. This is according to a study of blue tit birds led by Seyed Mehdi Amininasab of the University of Groningen in The Netherlands and Behbahan Khatam Alanbia University of Technology in Iran. The findings are published in Springer's journal Behavioral Ecology and Sociobiology.

Amininasab's team observed the nesting behavior of a population of blue tits (Cyanistes caeruleus) living in a forest of deciduous and conifer trees near Groningen in the Netherlands during the 2014 breeding season. More than 200 nest boxes designed with these songbirds in mind are set out in the area, and have been monitored since 2001. For the purposes of the present study, data loggers were placed in 92 of the nests to record temperature shifts during the incubation process. The researchers also captured the feeding behavior of males visiting 63 of these nests by using infra-red cameras. The results provide new insights into the effort that birds make to successfully incubate and hatch their eggs.

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Why the RSPB is withdrawing support for the Hen Harrier Action Plan

Martin Harper 

25 Jul 2016 6:55 AM 

The voluntary approach of the Hen Harrier Action Plan has failed, leaving licensing as the only viable option.

I’m generally very patient. My natural preference is to build partnerships and work to make positive change from the inside with those who want to abide by the law and deliver progress.

However, sometimes that approach simply doesn’t work and there can be no clearer example of that right now than hen harriers, where illegal killing of this rare bird remains its most significant threat.

The RSPB played a full part in the production of Defra’s Hen Harrier Action Plan and despitedisagreeing with certain points (notably brood management), welcomed its publication earlier this year. However, at the time, I noted the need for immediate progress to help build trust in the approach.

Unfortunately this has not happened. 

In 2015, we were all extremely frustrated by there being just six successful hen harrier nests from 12 attempts in England. 2016 is on course to be much worse, with only three nests at the time of writing, none of which are on grouse moors. 

Some will argue that the weather or vole population is to blame, however, early returns from the national hen harrier survey suggest numbers away from intensively managed grouse moors in north and west Scotland have done ok. We remain convinced that the primary reason for the hen harrier‘s continuing scarcity remains illegal killing. 

Simply put, hen harriers (and other birds of prey) are illegally killed on some estates because they eat grouse. Crimes are committed to increase the number of grouse that can be shot. This year, there have been a series of depressingly predictable incidents in England and Scotland, the disappearance of the hen harriers ‘Chance’ and ‘Highlander’, the use of pole traps and the hen harrier decoy in the Peak District. And as well as hen harriers, it has also been a really bad year for red kites in North and West Yorkshire with several suspicious deaths. In addition, there are more cases working their way through the legal system.

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Research reveals why males outnumber females in bird world

Date: July 7, 2016

Source: University of East Anglia

Female birds 'fly the nest' from sparsely populated breeding sites leaving behind small groups of lonely males -- according to new research from the University of East Anglia.

Research published in the Journal of Animal Ecology shows for the first time the causes of skewed sex ratios among small and declining bird populations.

The findings reveal how female birds are thought to be choosing busier breeding locations -- where habitat is often better, males are more abundant, and the ratio of males to females is more equal.

Lead researcher Prof Jenny Gill, from UEA's School of Biological Sciences, said: "Many migratory bird populations are declining and very small local populations are becoming more common.

"If females prefer places where males are more abundant, small populations are likely to decline even faster.

"However, the unpaired males will continue singing throughout the breeding season in a bid to find a mate, and so we may be underestimating declines in these small populations. We wanted to find out whether this was happening."

The research team used British Trust for Ornithology (BTO) ringing data to explore the extent, causes and consequences of varying sex ratios in breeding populations of willow warblers (Phylloscopus trochilus) across the UK.

Read on … 

Longest study of Great Lakes region birds finds populations holding steady

Date: July 12, 2016

Source: USDA Forest Service - Northern Research Station

A new USDA Forest Service report documenting an unprecedented effort to inventory birds in the western Great Lakes region and analyze changes in bird populations over the past quarter of a century found that across a trio of national forests, most birds are doing well in terms of both species diversity and population.

Published as General Technical Report NRS-159, "Analysis of Long-term Forest Bird Monitoring Data from National Forests of the Western Great Lakes Region" describes trends and potential drivers in the abundance of bird species. Gerald Niemi of the University of Minnesota-Duluth's Natural Resources Research Institute and Robert Howe of the University of Wisconsin-Green Bay are lead authors of the report with co-author Brian Sturtevant, a research ecologist with the USDA Forest Service's Northern Research Station. An estimated 700 birders have volunteered their time or worked as paid field researchers to inventory bird species for more than 25 years. The report will serve as a useful reference for forest managers identifying how species respond to forest management and what species need attention.

"Forest Service science is contributing to healthy, sustainable forests that are more productive and, ultimately, produce cleaner air and water," said Tony Ferguson, Acting Director of the Northern Research Station and the Forest Products Laboratory. "Forest birds play a vital role in forest stewardship through seed dispersal and insect control, and this research will be a valuable reference for land managers working to protect critical habitat for forest birds."

In the three national forests covered by the inventory -- the Chequamegon-Nicolet National Forest in Wisconsin and the Superior and Chippewa National Forests in Northern Minnesota -- the analysis found overall healthy bird communities that give researchers and policy-makers a degree of optimism. "It paints a picture of fairly healthy bird communities in these forests over two decades of surveys," said Niemi. "It shows that there is tremendous diversity of bird species in the region and emphasizes the importance of national forests to migratory and resident bird species."

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Alaska's shorebirds exposed to mercury

Date: July 13, 2016

Source: Central Ornithology Publication Office

Shorebirds breeding in Alaska are being exposed to mercury at levels that could put their populations at risk, according to new research from The Condor: Ornithological Applications.

Thanks to atmospheric circulation and other factors, the mercury that we deposit into the environment tends to accumulate in the Arctic. Mercury exposure can reduce birds' reproductive success and sometimes even be lethal. Shorebirds may be particularly vulnerable because they forage in aquatic environments where mercury is converted into methylmercury, its most dangerous form. Marie Perkins of the Biodiversity Research Institute (BRI) and her colleagues investigated the level of mercury in Alaska's shorebirds and found that some birds breeding near Barrow, at the state's northern end, have mercury concentrations upwards of two micrograms per gram of blood.

"These species already face a lot of tough new challenges, from climate change to disappearing stop-over habitat, so throwing a neurotoxin in the mix that can reduce reproductive success is likely to harm their populations," according to Dan Cristol of the College of William & Mary, an expert on mercury in birds who was not involved with the new study. "The mercury concentrations reported in this paper are likely to reduce reproduction, but not catastrophically, based on what we know from other species. What may be even worse, though, is that these mercury levels probably spike when they leave the breeding grounds and start burning their reserve fuel, making their already arduous continent-jumping trips even harder."

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Sex in the city: Peregrine falcons in Chicago don't cheat

Date: July 15, 2016

Source: Field Museum

Peregrine Falcons, in their normal habitat on isolated cliffs, mate for life. But some 25 pairs now nest on Chicago skyscrapers and bridges, and city living has them in much closer quarters than they used before humans dominated the landscape. A group of Field Museum and University of Illinois, Chicago scientists investigated whether typical breeding patterns hold true for these new city-dwellers and, in a paper published in PLOS ONE, confirmed that even in the big city, the birds that prey together, stay together.

"Peregrine Falcons that now live in the Chicago region are living in very different conditions than you'd normally see for these birds, so we wondered if the falcons' mating habits had changed too. They're in much closer proximity to each other than they'd be in a more rural environment, and we thought they might be more promiscuous with more potential mates nearby," explains co-author John Bates, Associate Curator of Birds at The Field Museum. "Each spring this population also has migratory Peregrines passing through on their way to all parts of Canada, so we didn't know what we were going to find, but it turns out that almost all of the mated pairs in the city remain monogamous through the years."

Peregrine Falcons nearly went extinct in the US in the 1960s due to thinning of their eggshells caused by the pesticide DDT. However, historic egg collections at the Field and other museums provided evidence for the harm caused by DDT, and it was banned. In the decades since, reintroduction efforts have enabled Peregrine Falcons to make a comeback in the Midwest, with populations thriving in urban areas in twelve states. Ninety percent of the breeding pairs in the Midwest nest on buildings and bridges in the Chicago area.

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Ornithologist captures rare Amur Falcon in Bastar

Rashmi Drolia| TNN | Jul 13, 2016, 09.52 AM IST

Raipur: Fondly called 'cutest falcon' by birdwatchers, Amur Falcon, a lesser known threatened species of raptor that breeds in south-eastern Siberia and Northern China was spotted for the first time in Central India's Bastar region by a birder recently.

Birder and head of department, zoology of Government PG College, Jagdalpur, Dr Sushil Dutta released his first research papers with photographic documentation on Tuesday.

He stated that Eastern red-footed Falcon, one of the least talked-about species, was spotted for two successive days while it was migrating from China to South Africa in November last year. Earlier, spotted in Gujarat and Andhra Pradesh, the Falcon crosses 22,000 kilometres via India and halts in MP and Chhattisgarh as well.

Dr Dutta told TOI, "On November last year, this bird first arrived at north eastern side of Rajnagar tank, about 26 kilometres from Jagdalpur. Thereafter, it moved on to a nearby power line and next morning, the bird was seen perched on the power line. These birds on their trans-equatorial migration come from China and north east and fly across to South Africa in the south west and Bastar seems to be the pathway on the route."

Dr Dutta added that they usually return in March-April from South Africa and fly away to far north east. But in February, March and April, I made several visits to the spot where I had sighted the bird but it was not to be seen."

It is the first ever photographic documentation of the bird in Central India. The two sighting events revealed most of the morphological characters helpful for identification.

Talking to TOI, ecologist ML Naik said, "Certainly it's a good report to know that area of distribution of species has been observed to be wider than earlier. Such news is good for the state if rare species of birds feel safe here. If they get food, they might stay longer, which is also an indication that state's area is safer and suitable for birds."

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