As you may have gathered from the title to this post, the bearded parrotbill is a species that has puzzled ornithologists for over two centuries. It is considered to be a member of the Paradoxornithidae family, but is thought to be an outlier in that family. It is the only parrotbill species to exhibit sexual dimorphism and a bill that bears no resemblance to other parrotbills. Subsequently the English name has changed from bearded tit to bearded reedling, and now to bearded parrotbill. There is no guarantee that this latest name will last long though, as according to molecular evidence the link with parrotbills may be a remote one.
We erected four nets at dawn and could hear bearded parrotbills calling their distinctive 'pinging' call almost immediately, but our first net round produced only three wrens. There have been at least 35 birds in the reedbed at Farlington and so we were hopeful of catching some birds, and and we didn't have to wait long.
|Male Bearded Parrotbill|
Male birds are striking and probably the most stunning breeding species in the British Isles. They are easily identified by the chestnut and white upperparts, grey head and throat and distinctive black moustache. The bright yellow bill and iris put the finishing touches to this beautiful species.
|Male Bearded Parrotbill - Note the characteristic black moustache that|
give the bird its name, grey head and rich chestnut and white upperparts.
Female birds are by contrast much duller and lack the distinctive moustache and the head is a buffish-brown colour. The wings are chestnut and white, as with the male birds, but not as bright.
|Female - Bearded Parrotbill - The female is much duller than the male and|
lacks the moustache and grey head.
Another striking feature of male birds are the black undertail coverts, which add to the overall stunning look of the species. Female birds lack the black and instead theirs are buff.
|Male and Female Bearded Parrotbills - Note the striking black undertail|
coverts of the male bird.
Ageing bearded parrotbills at this time of year can be tricky as both adult and juvenile birds undergo a summer complete moult and are therefore inseparable. Birds moult from mid-July through to late October and prior to that the 1st primary of a juvenile bird is longer than the longest primary covert, and its tip is rounded. In adult birds the 1st primary equals the length of the primary coverts and its tip is pointed. A feature which is used by some ringers is the colour of the iris, which is paler in juvenile birds and richer in adult birds. Of course this feature is only any good if you have experience with the species, or have several birds for comparison. Fortunately we caught 17 birds, 16 were new and one was a retrap and so we had plenty of birds to compare.
|Comparison in eye colour of full grown birds - the bird on the right is undoubtedly|
a bird of this year (age code 3), the bird on the left could be adult, or maybe a juvenile
from a first brood
The image above illustrates the difference in eye colour in two male birds. The right hand bird has a very pale, yellowish iris which would suggest a juvenile bird. In contrast the bird on the left, has an iris which is more orange in colour. This bird could be an adult, but the iris was still yellowish towards the outer edge which may indicate a juvenile bird but from a first brood. The image below illustrates two females, the bird on the right was an adult that was ringed at least two years before. Looking at the bird on the left, it again has a very pale iris indicating a juvenile bird. Another interesting feature is the colour of the bill, the adult birds bill is brighter, whereas the presumed juveniles bill is darker, this is not evident in the male birds.
|Comparison of eye colour in female birds. The right hand bird was a retrap|
that was at least two years old.
The session was not only memorable for the beardies but also for another species that I have not handled this year...a common stonechat. We had seen three birds feeding on the edge of the reedbed and suspected that there might be a chance of catching one or two. This bird was a juvenile (age code 3) male.
|Common Stonechat Saxicola torquata|
Adult stonechats undergo a complete moult after breeding, whereas juvenile birds undergo a partial moult. Therefore birds can be aged by the presence of retained juvenile feathers, evidence of wear and fringing. This bird exhibited a moult limit in the greater coverts and also a fair amount of wear and fringing in the wing and tail feathers, as seen below.
The surprise bird of the day was a sedge warbler, a species that should by now be well on the way to Africa. We have caught a few late birds during October at Titchfield Haven, but to catch this species in early November is exceptional. I looked back at the previous latest date for the species in Hampshire, and other than a previous bird that was recorded wintering on one occasion, the latest date is 9th November and that was in 1963. The latest bird in Hampshire in 2011 (2012 data not yet available) was 16th October.
|Sedge warbler Acrocephalus schoenobaenus|
By the end of the session we had caught 24 birds, 17 beardies, three wrens, and one each of robin, stonechat, Cetti's and sedge warbler. Looking at the forecast for the rest of the weekend it is doubtful that there will be anymore ringing.