A busy little session followed with 27 new birds and 2 retraps caught during the 2 hours the calm conditions lasted. It was interesting that 4 of the 10 Goldfinches caught were very fat and had bulging fat deposits in the tracheal pit and over the abdomen; these birds will be migrants that will be heading much further north and presumably to somewhere in Scotland or Northern Ireland to breed. One of the Blackbirds (a 2cy female) was similarly very fat and weighed a whopping 126.7g. A lean Blackbird weighs around 90g so this bird will have been carrying in the region of 35 to 40g of fat and will be migrating back to Scandinavia or somewhere further east fairly soon.
|Blowing back the feathers reveals the tracheal pit which is normally deeply concave in a bird that isn't carrying much or any fat but has been completely filled with fat and is bulging in this individual.|
The hedge on one side of the ringing site is full of ivy which is currently covered in ripe berries. These berries help migrant Blackbirds fatten up in readiness for the long journey back to their breeding grounds.
A Blackbird ringed at Crawford in the winter of 2016/17 was caught by ringers on the island of Utsira, off the coast of Norway, in spring last year and gives an indication of where today's fat Blackbird could be heading in the coming days.
Blackbird (Turdus merula) Ring no: LK25293
First year female 29-NOV-2016 Crawford, near Up Holland Lancashire, England
Caught by ringer 29-MAR-2018 Sore Merkeskog, Utsira, Rogaland, Norway
Duration: 485 days Distance: 795 km Direction: 37deg (NE)
Ringing totals (retraps in brackets) for 03/04/2019 were: Collared Dove 1; Coal Tit 1; Song Thrush 1; Blackbird 4; Tree Sparrow 8; Robin 1 (1); Chaffinch (1); Greenfinch 1; Goldfinch 10.