The end of winter (26 March 2005)
As the birds think winter has come to an end - almost all of our winter visitors have left, many of the resident birds are paired and on territories, and the bird population is at its lowest - it is probably a good time to publish some of the winter odds and ends that did not merit a specific page at the time.
The Bullfinch Pyrrhula pyrrhula is one of the few passerine species where the male and female often appear to stay together throughout the year, seemingly almost inseparable and thus often caught at the same time:
Bullfinch is also the species in which many ringers first become aware of the carpal covert, the small feather between the greater (secondary) coverts and the alula, because of the emphasis that Svensson places upon it in the Bullfinch text in his Identification Guide to European Passerines. The carpal covert is fringed with a brownish hue in first-year birds, while in adult birds it is edged greyish-white, as illustrated in the collection of three images below, showing (from left to right) first-year female, first-year male and adult male Bullfinches caught on 19 December 2004:
Although the age is easily determined from the state of the carpal covert, alula and primary coverts, there is also a clear moult limit in the greater coverts, the female having retained six old greater coverts (ogcs) and the male having three ogcs. The sharp-eyed reader will see that the female has retained a brown-edged median covert as well, as often happens with birds that have undergone an unextensive moult.
Note that the extent of the lighter-coloured tip of the greater coverts is rather variable, but reduces markedly from the innermost to outermost feathers. This effect, as seen on the adult male, could perhaps be mistaken for a moult limit by the unwary ringer.
In November 2004 a Goldcrest Regulus regulus was ringed that was displaying clear signs of ectoparasites, the feather-eating mallophaga. These show up as small white dots on many of the feathers, but the photograph is not one of the best as it was caught at dusk:
This bird's tail was also in very poor condition, with what appeared to be a severe fault bar right the way across all of the feathers:
A Greenfinch caught on 5 February 2005 graphically demonstrated the effects of having a growth bar. The central two rectrices had been replaced in its post-juvenile moult in autumn 2004, but the growth bar extending across all of the other feathers was so severe that they had all worn (or broken) off during the bird's normal activities. There have been frequent discussions on growth bars, and when does a growth bar become a fault bar: I think that bars as serious as these would surely merit the term 'fault bar'.
A Goldfinch Carduelis carduelis ringed on 24 October 2004 is a nice example of a first-year bird, Euring age 3, that had moulted two primary feathers (p5 and p6) in its post-juvenile moult. This phenomenon is seen more often in Greenfinches, but was previously illustrated for a Goldfinch on these pages on 25 August 2004. The first photograph below is probably better for seeing the more intense yellow coloration on the two moulted feathers, while the second image (lower left) is intended specifically to illustrate the darker black of the moulted feathers, and the more intense white and less worn feather tips. This is shown alongside the wing of a normal first-year bird caught on the same day to show the difference in colour and wear.
Information on Goldfinches with moulted primaries is being sought, along with that for other finches, as part of the widespread data collection exercise to determine the frequency of this phenomenon. Please contact us if you have data to contribute.
A male Nuthatch Sitta europaea ringed at a feeding station in Delamere Forest on 17 October 2004 had a somewhat deformed bill: the upper mandible (maxilla) and lower mandible are displaced sideways and do not meet. One of the advantages of having uniquely ringed birds is the ability to follow an individual through the years, and the same bird was retrapped twelve weeks later, on 9 January 2005. The set of photographs below show that the bill had clearly continued growing as the mandibles were unable to wear down by contact with each other.
The top three images are from 17 October 2004, and the bottom three from 9 January 2005; the apparent difference in the head colour arises from the colour balance of the camera, merely indicating that it was a murky day in mid-winter!
Birds like this might be expected to have difficulty in dealing with some natural foods, and are thus perhaps more likely to be found at feeding stations where food is frequently provided. Other aspects of daily life are likely to be problematic, such as feather maintenance, including preening and removal of ectoparasites, and it will surely have trouble, if it finds a mate, in the species' usual habit of sticking mud around its nest-hole.
Several Meadow Pipits Anthus pratensis were ringed on 13 January 2005 as part of our project collaborating with the University of Liverpool Veterinary School at Leahurst, studying 'The role of wildlife in the epidemiology of campylobacteriosis, salmonellosis and VTEC infections': birds such as the pipits, actively feeding in and around the farm slurry-pit, seemed especially important as possible carriers of such bacteria.
Pipits in northern Europe are notoriously difficult to age as many first-year birds have such a limited post-juvenile moult that moult limits cannot be seen. The image below shows the wing coverts of a first-year bird (Euring age 5 in January) on the left, and an adult bird (Euring age code 6) on the right. The first-year bird has mainly juvenile plumage, having moulted only some of its lesser coverts and the innermost median covert. It has retained all of its (juvenile) greater coverts, carpal covert, alula, and primary coverts, and the outer median and lesser coverts.
The characteristics for ageing that are visible in these photographs appear to be
However, the adult bird above appears to have accidentally retained the large feather of the alula (A3), this being a dull-brown colour with less buff fringing than any of the other feathers. This would appear to mark it down (in January) as a third-calendar-year bird, Euring age 7: would anyone be bold enough to put that on the schedule returned to the Ringing Office?
Finally in this collection, a very different bird: a Water Rail Rallus aquaticus caught at Woolston on 16 October 2004:
Its water-repellent plumage is well illustrated by the droplets on its head:
Its very long toes make it well adapted to walking in mud and across aquatic vegetation:
Some adaptations are easy to explain, but why do so many of the rails, crakes and related species all have white undertails?