Gyrfalcons are 'secret seabirds'

The world's largest falcon, the fast, taloned gyrfalcon, is a secret seabird, scientists have discovered.

Gyrfalcons living in the high Arctic overwinter out at sea, spending long periods living and hunting on pack ice.

It is the first time any falcon species has been found regularly living at sea.

The birds likely rest on the ice and hunt other seabirds such as gulls and guillemots, over what appears to be one of the largest winter ranges yet documented for any raptor.

Lees meer: BBC Nature

What the Duck? Lady Mallards May Get Down With Bright-Billed Drakes to Avoid STDs

When it comes to mallard bills, brighter is better: A bright yellow bill is duck-speak for “I’m healthy,” attracting more female ducks than dingy green ones. After discovering that avian semen has antibacterial properties, scientists then found that the semen of brighter-billed males killed more bacteria than the semen of darker-billed ones. It implies that by seeking out bright-billed males, female ducks are protecting themselves against bacteria-related sexually transmitted diseases.

Lees meer: Discover Magazine

Birds Dumping Eggs on the Neighbors

A huge study of over 69,000 nests around the west coast of Scotland has revealed for the first time the full extent of egg dumping by seabirds. The findings show that cuckoos aren't the only birds to lay eggs in other birds' nests, and may give an insight into how so-called brood parasitism evolved.

While the cuckoo is famous for laying its eggs in other birds' nests, this habit is rare and poorly understood among seabirds.

Lees meer: ScienceDaily

Migration and wintering areas of adult Montagu’s Harriers (Circus pygargus) breeding in Spain

Auteur(s): Ruben Limiñana, Alvaro Soutullo, Vicente Urios and Abilio Reig-Ferrer
Bron: Journal of Ornithology DOI: 10.1007/s10336-011-0698-x
Abstract: Between 2006 and 2008, 14 Montagu’s Harriers (Circus pygargus) were tagged with satellite transmitters at their breeding grounds in NE Spain, recording a total of 18 autumn and 10 spring journeys. In both autumn and spring migrations, harriers migrated between Europe and West Africa along a relatively narrow corridor between the coast of Morocco and Western Sahara and the western border of Algeria. Birds tended to follow a slightly more westerly track during spring migration compared to autumn migration. Harriers started autumn migration in late August–early September, arriving at their wintering grounds in early–mid-September, after travelling between 8 and 25 days, and covering a mean of 187 km a day. Spring migration started in mid-March, with birds arriving at the breeding grounds in mid-April after covering a mean of 114 km a day. On average, spring migration lasted longer, with birds covering longer distances than during autumn migration, and distances travelled in a day tended to be shorter. Significant differences in the routes followed by harriers were observed among seasons and individuals, with the same individuals following different routes in different years. Wintering areas were located in northern Senegal and the southern border of Mauritania with Mali, with some birds breeding in the same colony in Europe separated more than 1,200 km during the wintering season. Birds showed a relatively high fidelity to their wintering areas. Several birds moved from one area to another during the wintering period, which resulted in larger wintering areas, whereas others remained in the same area during the whole wintering season.