Showing posts with label Luscinia svecica. Show all posts
Showing posts with label Luscinia svecica. Show all posts

Sunday 28 June 2015

Red-spotted Bluethroats

An adult male red-spotted Bluethroat Luscinia svecica 


One of the more abundant passerines in northern Norway is the red-spotted Bluethroat, a robin-like bird that lives in birch and willow scrub, foraging for insects on the ground, while flicking from bush to bush. It is usually their tinkling song, or clicking contact call that gives away their presence, or thiier distinctive short flight low through the scrub.

An adult female red-spotted Bluethroat 


Most illustrations are of the brightly coloured males as they do have splendid throat colouring.  So I have added an image here of a female in breeding plumage. She has the basic colouring of the males, but duller and she has a darker, streaked breast than the males. This is because she needs to be less conspicuous while caring for her eggs and young.



Although conspicuous when singing from the top of a bush with their breast puffed up, most of the time, even male Bluethroats are secretive, passing quietly through the lower branches, dipping between shadows.

The intensity of the throat colouring varies between males and females, not all are bright, and the pattern varies in the amount of red in the spot, blue on the throat, or black, white and red on the lower bands. And I wonder how the birds see these colours, for the blue feathers have a shine to them, do the birds see an even brighter image via ultra-violet light sensitive visual perception?

The blue feathers on their throat, glisten in the sunshine, adding a marvellous metallic tint to the birds' plumage



Thursday 4 July 2013

Red-spotted Bluethroat

Adult male Red-spotted Bluethroat
While in Norway studying the waders in the marshes, we were constantly surrounded by the songs of local passerines. The main species were Willow Warbler Phylloscopus trochilus, Mealy Redpoll Carduelis flammea flammea and Red-spotted Bluethroat  Luscinia svecica svecica. As there are few ornithologists working in the field in northern Norway, to help discover the wintering ranges of these birds, we ringed any passerine chicks we came across and caught adults in mist nests. The warblers and redpolls do not vary much in plumage between breeding and wintering periods, but the Bluethroats were spectacular in full breeding plumage, especially the males.

The blue throat
The blue-throat of these birds is truly stunning, being of a metallic hue. It is so bright and obvious when seen in the filed, however, when in the hand and viewed face-on, these birds exhibit a clear and bright yellow gape. The yellow line complements the blue and red tones so well, it must have a purpose in the bird's display.

The abundance of waders and passerines in the Arctic is largely attributable to the supper-abundance of mosquitoes. They can be a pest for field-workers, with their incessant buzzing and biting, but without them the mires would not be such a tremendous breeding ground for birds - so many species are dependent on them for rearing their young.

Mosquitoes are ever-present in the Arctic scrub