Translated from the Dutch Sovon ornithologists:
Friday, July 3rd, 2015
To hear the raspy sound of the mysterious corncrake, this spring you had to go primarily to Groningen province. Nearly three-quarters of the birds counted are in this province, especially in the vast grain and alfalfa fields of the Oldambt region. This is evident from the special census Sovon has been organizing since 2000.
This video from the USA says about itself:
A harbor seal (Phoca vitulina) mother giving birth to a pup and their first swim. Footage was taken at a harbor seal rookery in southern Puget Sound, Washington during observations in 2004 under NMFS MMPA research permit # 782-1702. Video by Dyanna Lambourn, edited by Caitlin McIntyre, Washington Department of Fish and Wildlife.
Thursday, May 21, 2015
A newcomer to the GPS logger research is marsh harrier “Roelof”, an adult male provided last summer with a GPS logger. Roelof returned this spring to East Groningen, with a logger packed with GPS positions. He turned out to have had a highly remarkable journey! …
Roelof returned on April 15, 2015 in East Groningen, where he presented himself at the local antenna network where we can remotely read stored GPS data. …
In the autumn of 2014 Roelof flew via Spain to his first wintering area in Senegal, where he arrived on 27 September. This route falls exactly within the narrow migration flyway which is usual for marsh harriers. Christiane Trierweiler et al. described that harriers do not remain all winter in a single area, but during the winter they move to southern areas as the northern areas get dry. These are mostly trips of several hundred kilometers.
Roelof left his first wintering area on November 10 to land about 500 kilometers to the south in Guinea. To our surprise Roelof did not stay there until the end of the winter, but he left the area on January 26 to fly 1,700 kilometers along the West African south coast, eventually ending up all the way in Ghana! Ghana is really far away for a Dutch marsh harrier, outside the ‘normal’ wintering area.
On the shores of Lake Volta
In Ghana Roelof stayed around the shores of Lake Volta. This huge lake is probably a good wintering place for marsh harriers and the question is how he ever ‘found’ this place. Did he come here in his youth by chance, making the place by now a fixed point in his annual schedule? Or perhaps Roelof has eastern genes telling him that in winter this is the place to be? Monitoring young harriers will be the key to answering this kind of exciting questions.
Roelof left the Volta Lake on February 28, keeping a northwesterly course. Aided by a firm tailwind he was ‘blown’ across the Sahara until he reached the ocean coast in the Western Sahara. From there he continued his journey towards the northeast, where he made two short stops in Morocco (as befits a marsh harrier). From Morocco, he flew straight back to exactly the same reed bed in eastern Groningen …
This photo by Ben Koks shows marsh harrier Roelof, on the left, and his female partner. On Roelof’s back, one can see his GPS logger.
This is a marsh harrier video.
Translated from the Werkgroep Grauwe Kiekendief in the Netherlands:
Thursday, April 23, 2015
From 2009 on, the Werkgroep Grauwe Kiekendief [Montagu’s Harrier Workgroup] uses state-of-the-art UvA BiTS GPS loggers to map the movements of individual Montagu’s harriers in detail. In the vast East Groningen fields, however, besides Montagu’s harriers also hen and marsh harriers live. To compare how these three harrier species use the countryside precisely, the GPS logger investigation was expanded in 2012 to hen and marsh harriers.
A cold drizzly spring day in 2012 turned out to be a historic day in the marsh harrier research. This day was when near Delfzijl the first marsh harrier was caught for the GPS logger research. The male, called ‘William’ turned out to wear an aluminum ring of the bird migration research station. The ring data showed that William at the time was two years old, and had hatched in exactly the same reed bed where he nested now.
Different hunting pattern
It was exciting to follow the movements of William during the breeding season. William flew remarkably often along ditches, making a map of its track show the East Groningen allotment pattern. This contrasts with Montagu’s marriers, which also hunt in the central parts of fields and meadows. That William prefered to hunt along ditch banks was also evident from the prey remains found at his favourite place to sit, a striking number of ducklings and water voles.