Bird Population Declines In Northern Europe Explained By Thiamine (Vitamin B1) Deficiency

Wild birds of several species are dying in large numbers from a paralytic disease with hitherto unknown cause in the Baltic Sea area. A research team at Stockholm University, Sweden, led by Associate Professor Lennart Balk, has demonstrated strong relationships between this disease, breeding failure, and advanced thiamine (vitamin B1) deficiency in eggs, young, and adults.

Lees meer: ScienceDaily

Foraging in precocial chicks of the black-tailed godwit Limosa limosa: vulnerability to weather and prey size

Auteurs: Hans Schekkerman, Arjan Boele
Bron: JOURNAL OF AVIAN BIOLOGY, Volume 40 Issue 4, Pages 369-379
Abstract: Self-feeding precocial development is associated with high energy requirements and potentially vulnerable to short-term reductions in food availability, yet few studies have investigated development of foraging in precocial chicks and its sensitivity to environmental conditions. We studied time budgets and foraging behaviour during the 25-d prefledging period in the insectivorous chicks of a grassland shorebird, the black-tailed godwit Limosa limosa. Until 8–10  d old, parental brooding was the main determinant of chicks' daily foraging time. Brooding decreased with age and temperature and increased during rainfall. Foraging time increased to 70–90% of the daylight period in chicks older than a week, during which distances of 3–12  km  d−1 were covered. Chicks took 98% of their arthropod prey from the grassland vegetation. Prey ingestion rates increased in the first week and slowly declined thereafter, modified by wind speed, temperature and time of day. Chicks in poor body condition were brooded more than chicks growing normally and hence had less feeding time, potentially leading to a negative condition spiral under adverse conditions. However, we found no effect of condition on prey ingestion rate that would preclude recovery when conditions improve. Combining behavioural observations with data on energy expenditure revealed that mean prey size was small (1–4.5  mg), necessitating a high feeding rate, but increased notably after 7–10  d of age. This coincided with a decrease in walking speed, suggesting that chicks fed more selectively. Prey of older chicks approached the upper limit of sizes available in exploitable densities in the grassland vegetation, and this enhances the chicks' sensitivity to variation in prey availability due to weather and agricultural practice.

Huge declines in woodland birds

The nightingale has effectively vanished from woodlands across the UK.

A 30-year survey of British woodland birds has found that its population has fallen by more than 95%.

Seventeen other bird species have also declined significantly, many of which overwinter in tropical west Africa where their habitat is being destroyed.

Numbers of starling, linnet, bullfinch and willow warbler all crashed, while 12 species, including the blackcap, magpie and collared dove, increased.

These startling trends in the populations of some of the UK's best known woodland birds comes from the British Trust for Ornithology's (BTO) Common Bird Census, which gathered data on 49 species between 1967 and 1999.

Lees meer: BBC News

Birds With A Nose For A Difference: Avoidance Of Inbreeding In Birds Demonstrated

Avoidance of inbreeding is evident amongst humans, and has been demonstrated in some shorebirds, mice and sand lizards. Researchers writing in the open access journal BMC Evolutionary Biology now report that it also occurs in a strictly monogamous species of bird, suggesting that the black-legged kittiwake possesses the ability to choose partners with a very different genetic profile.

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Oldest bird's nest found

The world's oldest bird of prey nest that is still in use has been discovered in Greenland but climate change may threaten its continuing use, believe ornithologists.

Gyr Falcons will reuse a successful nest for thousands of years. Photo: Derek Bakken (Wikimedia commons)

Many birds of prey use traditional nest sites year after year. To find out just how long some nests have been in use, ornithologists in Greenland carbon dated the guano and other debris around Gyr Falcon nests. 

Three other nests, each over 1,000 years old, have also been found, one of which contains feathers from a bird that lived more than 650 years ago. But one nest from central-west Greenland beat these being between 2,360 and 2,740 years old.

Lees meer: Birdwatch