Godwit and knot migration

Grutto 2 from Erik Veldkamp on Vimeo.

This is a black-tailed godwit video.

Today was a special day for BirdLife in the Netherlands in the natural history museum.

Part of it was a joint presentation by ornithologist Theunis Piersma and musician Sytse Pruiksma, about black-tailed godwit migration. About 60% of all black-tailed godwits nest in the Netherlands.

A central role in the presentation, a combination of lecture, slideshow and music performance, was played by female godwit A99.

She was born on 16 May 2008, the day she was ringed in Friesland province.

Then, nothing was heard about her, until a bird researcher identified her by her ring in rice fields in Extramadura in Spain in January 2009. Many Dutch black-tailed godwits winter there from January till the end of February, after returning from autumn migration to western Africa and before spring migration to the Netherlands.

Black-tailed godwits are high altitude migrants, from 500-2500 meter in the air. They migrate in V shaped groups, somewhat like geese, to divide the effort of flying against the wind equally among fellow travelers.

After godwits return to the Netherlands in early spring, they often congegrate in big groups in marshy areas like the Landje van Geijsel; see photos here. Then, they do not eat rice like in their winter quarters, but worms, which they can reach now that the soil is not frozen any more. Gradually, from there they spread to their nesting zones.

In the spring of 2009, godwit A99 returnmed to her native Friesland. A three year old male godwit became her mate. Three eggs came, and three chicks fledged and were ringed. Their mother A99 was provided with a transmitter in order to follow her migration movements. Adult godwits leave for Africa some time before young godwits.

In late summer, A99 first flew west from Friesland to Noord-Holland province. Then, to Belgium. Then to Spain, and to Morocco. On 23 August, she was in Senegal.

Relatively few godwits die during migration. Their problem is the low survival rate of chicks in the Dutch breeding grounds. More intensive agriculture means higher mortality of youngsters. Usually, in nature reserves 50% of meadow bird chicks survive; in commercial farm areas just 15%. However, 2010 was an unusually wet year. That meant that farmers could start mowing grass with big machines later than usually, which gave chicks a better chance. This year, the survival rate of chicks was 50% everywhere.

Mr Piersma said that the problems of godwits in the Netherlands were part of the problems of migratory shorebirds world wide. Siberian red knots, eg, migrate to the Chinese Yellow Sea wetlands, then to Australia to winter. At the moment, many of those Chinese wetlands are being drained, which causes big problems for the red knots.

Red Knots non-stop flight and total migration distance: here.

Aves Argentinas: New tool for bird-banding studies: here.

Record number of birds ringed in UK: here.

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