For pigeons, follow the leader is a matter of speed

Many birds travel in flocks, sometimes migrating over thousands of miles. But how do the birds decide who will lead the way? Researchers reporting in the Cell Press journal Current Biology on November 25 now have some new insight based on studies in homing pigeons. For pigeons, it seems, leadership is largely a question of speed.

"This changes our understanding of how the flocks are structured and why flocks of this species have consistent leadership hierarchies," says Dora Biro of the University of Oxford.

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Birds Use Nanostructures To Prevent Graying With Age

Going gray is something most people worry about at some point in their lives. Curiously, birds do not share the same problem, as their plumage always remains a vibrant collage of colors until they die. Scientists have now discovered how this is possible, at least in terms of the Eurasian Jay: It generates its patterns by manipulating the growth of many tiny structures on its feathers, instead of using dyes or pigments that would fade over time. The new findings are published today in the journal Scientific Reports.

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Gulls follow ducks for dinner

Gulls in central Europe have learned to follow diving ducks to take the bottom-dwelling mussels that would otherwise be inaccessible to them.

Gulls are well known as one of the most adaptable groups of birds, able to exploit a wide variety of food resources and respond to new opportunities, and a new study in American journal The Auk documents this previously unrecognised behaviour in Herring Gulls and Common Gulls on a brackish lagoon on the border between Germany and Poland.

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Cuckoo sheds new light on the scientific mystery of bird migration

The cuckoo is not only capable of finding its way from unknown locations; it does this through a highly complex individual decision making process. Such skills have never before been documented in migratory birds. A new study shows that navigation in migratory birds is even more complex than previously assumed. The Center for Macroecology, Evolution and Climate at the University of Copenhagen led the study with the use of miniature satellite tracking technology.

In an experiment, 11 adult cuckoos were relocated from Denmark to Spain just before their winter migration to Africa was about to begin. When the birds were released more than 1,000 km away from their well-known migration route, they navigated towards the different stopover areas used along their normal route.

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A 'supergene' underlies genetic differences sexual behaviour in male ruff

The ruff is a Eurasian shorebird that has a spectacular lekking behaviour where highly ornamented males compete for females. Now two groups report that males with alternative reproductive strategies carry a chromosomal rearrangement that has been maintained as a balanced genetic polymorphism for about 4 million years.

The two studies, one led by scientists at Uppsala university, are published today in Nature Genetics.
Three different types of ruff males occur at the leks of this species. 'Independent' males show colourful ruffs and head tufts and fight vigorously for territories. 'Satellite' males are slightly smaller than Independents, do not defend territories and have white ruffs and head tufts. 'Faeder' males mimic females by their small size and lack of ornamental feathers, they do not defend territory.

Lees meer: Biology News Net

A poor start in life creates differences in eating behavior modeled in starlings

A Newcastle University study has shown that baby birds that have a difficult start in life grow to be fatter and greedier than their more fortunate siblings.

The researchers, led by Professor Melissa Bateson and Dr Clare Andrews, discovered that stress and difficulties as a chick made a long lasting impression on a starling's relationship with food.

The study, published in the journal Animal Behaviour and funded by the BBSRC, showed that the smallest chicks in European starling families changed their adult feeding behaviour, resulting in a fatter body composition in the fully developed birds.

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Birds Give Up Food to Stay Close to Their Mates

When forced to choose, some songbirds prefer the company of their mates to a good meal.

Social living entails some compromise; that’s as true for birds as it is for people. Foraging in flocks often means that some birds get a little less food than they might by flying solo, but there is also safety in numbers: flocks provide better defense against predators and more eyes to watch for danger. For most, a little food for a lot of security is a worthwhile tradeoff. Some songbirds, it turns out, are willing to make even greater sacrifices for the sake of staying close to their mates.


Great tits – small songbirds with yellow, black, and white feathers – seem perfectly willing to spend time at a feeder where they can’t get any food, in order to stay close to their mates who can eat there.

Lees meer: Discover Magazine

Why Great Tits get 'divorced'

The likelihood that a pair of Great Tits will stay together after they first breed is influenced by the social environment in which their relationship is formed, a new study says.

Much like humans, birds tend to be socially monogamous: they find a partner to mate with and remain socially exclusive with this partner. Also like humans, they sometimes cheat on their partners or separate to copulate with a different mate, and this often happens when the social partnership is sub-optimal.

Lees meer:  Birdwatch

How do migrating birds avoid predators while fueling up?

Birds stopping for a break during their grueling migratory flights face a difficult tradeoff: They need to fuel up with food as efficiently as possible, but they need to avoid predators while they do it. To learn more about how they make these choices about food availability and predator risk, Jennifer McCabe and Brian Olsen of the University of Maine's Climate Change Institute spent two years capturing birds during fall migration along the coast of Maine. Their results, published in The Auk: Ornithological Advances, show that overall birds prefer to stop in habitat with plenty of dense vegetation in which they can hide from predators such as hawks. However, the longer the migration a bird is facing, the more likely it is to take risks in order to fill up with high-energy fruit.

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Songbird habitat affects reproduction, survival

A University of Montana professor who studies birds around the world has discovered trends in how the offspring grow, how parents care for the young and how well the young survive based on where they live. Now, his songbird research is hitting the right notes with the journal Science.

Thomas Martin, assistant leader of the U.S. Geological Survey Montana Cooperative Fish and Wildlife Research Unit at UM, set out to explain why tropical birds tend to have fewer offspring that seem to grow slower and live longer, slower lives than their northern counterparts. He found tropical songbirds grow their wings faster, aided by higher parental feeding rates for fewer offspring than temperate species. Those differences, Martin said, ultimately translate to how well the offspring escape predators both in the nest and after they leave it.

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Late-Rising Birds Become Cuckolds

You snooze, you lose paternity. That’s the message of a new study on wild birds in Germany. Males that wake up the earliest are able to sneakily mate with other birds’ partners. Males that sleep in, meanwhile, get stuck raising young that aren’t their own.

Great tits (Parus major) appear monogamous at first glance. They stick with one partner and cooperate to raise their young. But, like many other birds that scientists call “socially monogamous,” they sleep around. Great tit nests often contain eggs from more than one father.

North Dakota State University biologist Timothy Greives knew from previous studies that songbirds often use the early morning for their trysts. This could mean that males who are true early birds have a better chance of finding extra partners—and guarding their own partners from other males. Supporting this idea, a study in blue tits showed that males have greater mating success outside their home nests if they start singing earlier in the morning.

Lees meer: Discover Magazine

Using habitat selection theories to predict the spatiotemporal distribution of migratory birds during stopover – a case study of pink-footed geese Anser brachyrhynchus

Auteurs: Magda E. Chudzinska, Floris M. van Beest, Jesper Madsen, Jacob Nabe-Nielsen

Bron: Oikos Article first published online: 6 FEB 2015 DOI: 10.1111/oik.01881

Abstract: Understanding how animals select for habitat and foraging resources therein is a crucial component of basic and applied ecology. The selection process is typically influenced by a variety of environmental conditions including the spatial and temporal variation in the quantity and quality of food resources, predation or disturbance risks, and inter- and intraspecific competition. Indeed, some of the most commonly employed ecological theories used to describe how animals choose foraging sites are: nutrient intake maximisation, density-dependent habitat selection, central-place foraging, and predation risk effects. 

 Even though these theories are not mutually exclusive, rarely are multiple theoretical models considered concomitantly to assess which theory, or combination thereof, best predicts observed changes in habitat selection over space and time. Here, we tested which of the above theories best-predicted habitat selection of Svalbard-breeding pink-footed geese at their main spring migration stopover site in mid-Norway by computing a series of resource selection functions (RSFs) and their predictive ability (k-fold cross validation scores). At this stopover site geese fuel intensively as a preparation for breeding and further migration. 

We found that the predation risk model and a combination of the density-dependent and central-place foraging models best-predicted habitat selection during stopover as geese selected for larger fields where predation risk is typically lower and selection for foraging sites changed as a function of both distance to the roost site (i.e. central-place) and changes in local density. In contrast to many other studies, the nutritional value of the available food resources did not appear to be a major limiting factor as geese used different food resources proportional to their availability. Our study shows that in an agricultural landscape where nutritional value of food resources is homogeneously high and resource availability changes rapidly; foraging behaviour of geese is largely a tradeoff between fast refuelling and disturbance/predator avoidance.

Why fledge early in the day? Examining the role of predation risk in explaining fledging behavior

Auteurs: Scott J. Chiavacci, Michael P. Ward, Thomas J. Benson
Bron: Behavioral Ecology (2015) 26 (2): 593-600. doi: 10.1093/beheco/aru236
Abstract: Predation represents the primary cause of mortality for both nestling and fledgling birds and is often greatest in the days immediately before and after nest departure. Due to the selective pressures of such high mortality rates, behaviors likely evolved to increase the survival of young. Among altricial species, fledging often occurs in the morning with most nestlings leaving within 6h of sunrise.
However, why nestlings tend to fledge in the morning and whether this strategy is a response to predation risk is unknown. We investigated how the time of day when fledging began and how rapidly broodmates fledged were influenced by nest predation rates and nest site features that affect nest predation risk.
We video recorded 477 fledging events at 202 nests of 17 species. Nestlings occupying nests with greater predation risk initiated fledging earlier in the day than those at safer nests. Similarly, broodmates in riskier nests fledged over a shorter period of time than broodmates in safer nests. Our findings support the hypothesis that predation risk influences the time of day when fledging occurs. By fledging earlier and more quickly, young in high risk nests presumably decrease their chances of being depredated in the nest, whereas those occupying safer nests are likely under reduced pressure to fledge as early and quickly as possible. These results indicate that nestlings preparing to fledge likely face more complex situations than currently understood, and the timing of nest departure is an important decision made in an effort to maximize fledgling fitness.

A beggars banquet: Carrion crow chicks sit back while cuckoo chick does all the begging

It’s not all bad for crow chicks who have to share their nest with an uninvited pushy guest such as a cuckoo youngster. For one, they can sit back and wait for food to arrive while the cuckoo chick does all the begging for nourishment. So says a researcher who led a study into the pros and cons associated with the parasitic relationship of the great spotted cuckoo with the carrion crow.

Lees meer: ScienceDaily

Bad reputation of crows demystified

In literature, crows and ravens are a bad omen and are associated with witches. Most people believe they steal, eat other birds' eggs and reduce the populations of other birds. But a new study, which has brought together over 326 interactions between corvids and their prey, demonstrates that their notoriety is not entirely merited.

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Species of bird 'paints' its own eggs with bacteria to protect embryo

Researchers from the University of Granada and the Higher Council of Scientific Research (CSIC) have found that hoophoes cover their eggs with a secretion produced by themselves, loaded with mutualistic bacteria, which is then retained by a specialized structure in the eggshell and which increases successful hatching. So far this sort of behaviour has only been detected in this species of birds, and it is a mechanism to protect their eggs from infections by pathogens.

Lees meer: ScienceDaily