Saturday, June 4, 2011

We wanted to start this post with a big thank you to all the people who have left such supportive comments about our blog over the last few weeks, they are very much appreciated.

Spotted Flycatchers and Chiffchaffs continue to pass through in small numbers and scarcer late migrants have included another Cuckoo, a couple of Reed Warblers, a Reed Bunting and a few Swifts and Lesser Redpoll. A flock of 15 Collared Doves was notable and bird of the last few days went to a cream-crown Marsh Harrier, the third of the year, which flew north past myself and Giselle as we relaxed with a beer after a hard days seabird ringing. Monitoring the seabirds of Bardsey, and yesterday on the nearby Gwylan Islands, is taking up the majority of our time and our hands and arms are gradually getting more and more battered as successive Shags, Cormorants and Razorbills chew and scratch us as we ring them.

Approximately 1000 pairs of Guillemot breed on Bardsey in many sub-colonies dotted around the coastline. Breeding Guillemots are monitored by counting the number of adult birds occupying suitable breeding habitat. Using a camera makes this process a lot easier as it can be rather tricky from a gently bobbing boat. In this particular photograph there are 57 adults on ledges. (c) Richard Brown

Guillemots nest in tight groups of up to 70 birds per square metre and birds may be in physical contact with several neighbours. They thus defend the smallest known nest-area territory of any bird species, somewhere in the region of 0.05 square metres. This comprises the nest site and an adjacent area on which a off-duty parent may loaf. The territory is used for part of the courtship process, copulation and raising of the single chick. The territory may move slightly if the egg moves. Both adults defend the territory, tolerating adjacent incubators but attacking non-incubators closer than about 15cm. (c) Richard Brown

There are usually around 300 apparently occupied Kittiwake nests each year. Kits differ from most other gulls in that they nest in high densities on small cliff ledges and build more elaborate nests which are not camouflaged. Older birds generally nest closer to the centre of the colony and lay their eggs earlier than the younger, less experienced birds which frequent the edges. 

We visit the nearby Gwylan Islands each year as part of our seabird monitoring programme. Here there are up to 130 pairs of shag, 80 pairs of Cormorant, 60 pairs of Great Black-backed Gull and 1000 pairs of Puffin along with smaller numbers of other auks and, for the first time this year, a pair of Canada Goose. This is the view from Ynys Gwylan Fawr to Ynys Gwylan Bach with Ynys Enlli (Bardsey) in the distance. (c) Giselle Eagle

Giselle having ringed her first Cormorant chick. This year is looking really good for Cormorant with many large young throughout the colony. (c) Richard Brown

Young Cormorant are usually fed twice a day, once by each adult, on regurgitated fish. If the chicks are thirsty they beg with an upwards wave of a wide open mouth. This encourages the off-duty parent to go and fetch water in their throat for the chicks to then drink. (c) Richard Brown

This adult male Shag was one of over 80 Shags ringed on the Gwylans yesterday. It was sexed by the way it was calling. Males grunt loudly, a noise which can be heard for up to 300 metres. Females make throat clicking noises, as can males, but they are otherwise voiseless. The lower photo shows Rich ringing the bird in the best way so as to avoid being lacerated. (c) Giselle Eagle

Great Black-backed Gull chicks may leave the nest as soon as they are dry after hatching or may remain in the nest for a couple of days before hiding, incredibly well, nearby. The adult birds make mewing calls to stimulate the chicks to beg for food. The young chicks will then feed from the adult's bill, but as they get older the adults will regurgitate their food onto the ground. (c) Richard Brown

Puffins are monogamous and show very high nest burrow fidelity. They first breed when they are five or six years old. Immature birds younger than this will start to visit colonies at this time of year when the breeding birds are busy bringing in Sand Eels to their young. The immature birds visit the colony progressively earlier as they age each year until they breed for the first time. (c) Giselle Eagle

The view home after a fantastic sunny day spent seabird monitoring. A beer on the boat, as Manx Shearwaters glided alongside, finished it off nicely. (c) Giselle Eagle

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