Island Birds Can Adapt to Predators, Study Suggests

An island bird in New Zealand is able to change its nesting behavior to outwit predators—offering a ray of hope for island species worldwide facing threats from exotic invaders—researchers have discovered.

Melanie Massaro, a biologist at the University of Canterbury, and her co-authors found that New Zealand bellbird mothers spend longer periods of time on their nests when the risk of predation rises.

Lees meer: National Geographic News

Birds communicate reproductive success in song

Some migratory songbirds figure out the best place to live by eavesdropping on the singing of others that successfully have had baby birds – a communication and behavioral trait so strong that researchers playing recorded songs induced them to nest in places they otherwise would have avoided.

This suggests that songbirds have more complex communication abilities than had previously been understood, researchers say, and that these "social cues" can be as or more important than the physical environment of a site.

Lees meer: Biology News Net

SORA - Searchable Ornithological Research Archive

A full text searchable ornithological archive with following journals:

• Auk (1884-1999)
• Condor (1899-2000)
• Wader Studies Group Bulletin (1970-2004)
• Journal of Field Ornithology (1930-1999)
• Journal of Raptor Research (1967-2005)
• North American Bird Bander (1976-2000)
• Ornithological Monographs (1964-2005)
• Pacific Coast Avifauna (1900-1974)
• Studies in Avian Biology (1978-1999)
• Western Birds (1970-2004)
• Wilson Bulletin (1889-1999)

SORA

The watchman's song

Soldiers on sentry duty in hostile territory keep in regular radio contact with their colleagues to assure them that all is well and that they are safe to carry on their manoeuvres. New research by Dr Andy Radford of the School of Biological Sciences reveals that this is also a feature of the bird world.

Lees meer: Physorg.com

A flyway perspective on food resource abundance in a long-distance migrant, the Eurasian teal ( Anas crecca )

Auteur(s): Céline Arzel, Johan Elmberg, Matthieu Guillemain, Michel Lepley, Fabrice Bosca, Pierre Legagneux and Jean-Baptiste Nogues
Bron: JOURNAL OF ORNITHOLOGY Online First DOI 10.1007/s10336-008-0318-6
Abstract: Two frequent assumptions about the evolution of long-distance migration in birds are that they travel long distances annually to reach food-rich areas for breeding, and that they time their migratory journey to be at staging sites when the latter provide the best feeding conditions. These assumptions have rarely been properly tested, and there is no study in which a species’ major food types have been measured by standardized methods throughout a flyway and over a large part of the year.
We here present such data for Eurasian teal (Anas crecca), converted to a common energetic currency, and collected at wintering, spring staging and breeding sites. Teal did not time migration to maximize local food abundance; most birds left wintering and spring staging sites before a sharp increase in invertebrate food abundance occurred. On the other hand, hatching of ducklings coincided with a peak in invertebrate food abundance on boreal breeding lakes. Mean overall food abundance (invertebrates and seeds combined) did not differ between wintering sites in southern France and breeding sites in northern Sweden at the time of breeding.
Our results are inconsistent with the hypothesis that long-distance migration in dabbling ducks has evolved because adult birds gain an immediate pay-off in increased food abundance by flying north in spring. However, our data confirm a selective advantage for breeding at higher latitudes, because hatching of ducklings may coincide with a peak in invertebrate emergence and because longer days may increase the duration of efficient foraging.

Fuel stores, fuel accumulation, and the decision to depart from a migration stopover site

Auteur(s): Schaub, M; Jenni, L; Bairlein, F
Bron: BEHAVIORAL ECOLOGY, 19 (3): 657-666; MAY-JUN 2008
Abstract: Birds usually migrate by alternating flight bouts and stopovers for refueling. The decision when to leave a stopover place is of paramount importance for the success of migration. Despite its importance, little is known about which factors influence the departure decision. Using capture-recapture data of passerines from 3 stopover sites, we investigate by capture-recapture models whether this decision is dependent on actual fuel stores and fuel deposition rates. Individuals that accumulated fuel stores at medium rates departed later than individuals that either lost fuel stores during their stopover or able to increase their fuel stores quickly. This pattern was consistent among all sites. The departure decision was not dependent on actual fuel stores at 2 stopover sites. At the site facing an ecological barrier, emigration probability increased with increasing fuel stores, indicating that birds wait until they reach a threshold of fuel stores before departing.
There was a positive correlation between departure fuel load and fuel deposition rate at all sites, which is in accordance with the time-minimizing hypothesis.
These results suggest that the decision to depart from a stopover site is based on rather simple behavioral rules: birds that lose fuel stores or that increase fuel stores at a high rate would leave a site quickly, whereas birds increasing fuel stores at intermediate rates would stay for a longer time. The departure decision is shaped also by the position of the stopover site in relation to the next one and may be affected further by environmental factors.

Plasticity of moult and breeding schedules in migratory European Stonechats Saxicola rubicola

Auteur(s): HEINER FLINKS, BARBARA HELM, PETER ROTHERY
Bron: IBIS OnlineEarly Articles doi:10.1111/j.1474-919X.2008.00833.x
Abstract: Timing is crucial in seasonal environments. Passerine birds typically use a combination of physiological mechanisms and environmental cues to ensure that breeding, moult and migration occur without major temporal overlap and under the most favourable conditions. However, late in the breeding season some individuals initiate additional clutches , whereas others initiate moult. Such alternative strategies are thought to reflect trade-offs between reproductive benefits and timely investment in maintenance and survival. The degree of seasonal plasticity differs between species, depending on the mechanisms that govern their annual routine. Migrants are generally under pressure to complete breeding and moult before the autumn departure and often show little plasticity.
We studied seasonal plasticity of breeding and moult schedules in the European Stonechat Saxicola rubicola. This species, an obligate short-distance migrant in Central Europe, sometimes initiates late clutches after typically at least two earlier breeding attempts. Based on life-history theory and on observations in captivity, which revealed photoperiodic regulation of breeding and moult, we predicted relatively little seasonal plasticity in Stonechats. We further predicted that reproductive gains of late breeders should be offset by reduced survival. These predictions were tested on long-term field data, using Underhill–Zucchini models to estimate moult. Late breeding occurred in c. 40% of pairs and increased their reproductive success by a third.
Both sexes modified moult timing but in different ways. Late breeding females postponed moult approximately until chick independence without compensating for delay by faster moult. Males started moult on time and overlapped it with breeding, associated with markedly slowed plumage change. Sex differences in moult score increased with lay date, but due to their respective modifications, both sexes delayed moult completion. Nonetheless, we could not detect any evidence for survival costs of late breeding.
Breeding and moult of European Stonechats appear relatively flexible, despite migratory schedules and photoperiodic programs for seasonal timing. Individuals can modify seasonal behaviour in late summer, presumably depending on their condition, and may profit considerably from extended breeding.

Complete 'family tree' of all British birds gives clues about which species might be endangered next

A new complete evolutionary 'family tree' showing how all British bird species are related to each other may provide clues about which ones are at risk of population decline, according to new research published today (11 June) in Proceedings of the Royal Society B: Biological Sciences.

Comparing the new family tree with existing lists of endangered bird species, author Dr Gavin Thomas from the NERC Centre for Population Biology at Imperial College London found that British birds currently suffering population decline were clustered close together on the same branches of the family tree.

Lees meer: Biology News Net

New Zealand Bird Outwits Alien Predators

New research led by Dr Melanie Massaro and Dr Jim Briskie at the University of Canterbury, which found that the New Zealand bellbird is capable of changing its nesting behaviour to protect itself from predators, could be good news for island birds around the world at risk of extinction.

The introduction of predatory mammals such as rats, cats and stoats to oceanic islands has led to the extinction of many endemic island birds, and exotic predators continue to threaten the survival of 25 percent of all endangered bird species worldwide.

Lees meer: Science Daily

Loch Garten ospreys live

The osprey nest at the top of a tree at Loch Garten.

RSPB Abernethy Forest nature reserve

• The female osprey, 'EJ', arrived back at the nest on 26 March
• The first egg was laid on the morning of 18 April. The chicks hatched on 24 May, 26 May and 29 May. For the latest news, please read our blog
• Ospreys survive solely on fish
• Ospreys travel thousands of miles from African wintering grounds to breed here
• They are mainly found in Scotland, but also in the English Lake District, Rutland Water in the English Midlands and at Glaslyn in north Wales

RSPB Live Video

The Cormorant -- The 'Black Plague' Or An Example Of Successful Species Conservation?

Europe requires a common management strategy for cormorants in order to reconcile nature conservation and fishing interests. An effective regulation of cormorant populations can only work at the European level, researchers from the Helmholtz Centre for Environmental Research (UFZ) write in the scientific journal Environmental Conservation. Furthermore, they suggest a five-step action plan, which would start with a consensus on the real numbers of animals and end in an international management plan.

Currently a common solution is not materialising because of too many different interests from individual countries and a lack of coordination, according to UFZ researchers. In North America by comparison, a management plan for the Double-crested Cormorant has been in operation since 2003, although the problem there is just as complex as it is in Europe. The size of the cormorant population in Europe varies between half a million and one and a half million birds, depending on who provides the data. The researchers’ vision of a new action plan materialised from 22 interviews conducted with responsible persons from several EU countries at different management levels.

Lees meer: Science Daily

For barn swallows, feathers make the man

A new study led by the University of Colorado at Boulder has shown the testosterone of male North American barn swallows skyrocketed early in the breeding season when their breast colors were artificially enhanced by researchers, indicating the clothes -- or in this case, the feathers -- make the man.

The swallows, whose breast feathers were darkened to a deep red known to be most attractive to females, likely had more testosterone racing through their bodies because of amorous interactions with the opposite sex and more run-ins with jealous males, said CU-Boulder Assistant Professor Rebecca Safran, lead study author. The jump in testosterone was unexpected because it was observed at the time in the breeding cycle when levels of sex steroids like testosterone are typically declining, she said.

Lees meer: Biology News Net

Antarctic Melt Releasing DDT, Tainting Penguins

Poisonous chemicals that had been locked in ice for decades are now being released as climate change melts Antarctic glaciers, researchers report.

The chemicals, including the pesticide DDT, are seeping into the polar ecosystem and finding their way into wildlife populations.
Scientists made the discovery when studying the levels of pollutants in the fat and eggs of Adélie penguins.

Lees meer: National Geographic News