Nest miscellany II - passerines (25 August 2004)
This section is so large that it is split into two - non-passerines and passerines - to ease the load on machines with a slow internet connection.
Members of Merseyside Ringing Group spend a major part of the spring and summer months in studying nests, completing Nest Records for submission to the BTO's national collection. Where possible, nests are monitored and the chicks (pulli) ringed at the appropriate stage. These pages cover a range of sites and dates to illustrate the variety of data acquired for some passerines.
The nests of open-nesting passerines can be quite challenging to find. Chaffinches Fringilla coelebs are well-hidden, often in a hedge such as hawthorn Crataegus monogyna or low down in a tree or bush. This nest was tracked from when the adults were building and the chicks ringed at six days of age, when their legs are at about their maximum diameter. The tufts of down on the chicks' backs and heads allow them, at a casual glance, to merge into the nest lining:
Whinchat Saxicola rubetra, the closest British relative of Stonechat Saxicola torquata, is now probably extinct as a breeding bird in lowland Cheshire but still quite common in the nearby Welsh hills, and a couple of MRG members ringing in that area are responsible for a high proportion of the national total of Whinchat Nest Records. Nests are often, as is this one, well hidden in bracken Pteridium aquilinum, with the photograph showing the chicks asleep after being returned to the nest by the ringer:
Next is a charming photograph of a brood of Wrens Troglodytes troglodytes, the species known in North America as the Winter Wren. These chicks are nearly ready to fledge and would almost certainly 'explode' from their nest if touched. Unusually, a Wren's nest is built by the male bird: the cocks build several nests, from which the female chooses one, and lines it herself. This nest was in a the wall of an old stone building; when checked a few days later it was empty, with feather scale and droppings around the entrance – a sure sign of successful fledging and a nice outcome for the Nest Record Card to be sent to the BTO.
The photograph below is of an unusual Wren's nest. If you had found this nest, in a hawthorn hedge, later in the season, you would probably think you had missed a brood of Dunnocks Prunella modularis. But when the ringer came across it, she witnessed at least five Wrens leave it and saw adults feeding others nearby. An un-domed Wren’s nest in a hedge is virtually unheard of, and is not mentioned in any of the classic books on birds' nests such as A Field Guide to Birds' Nests, by Bruce Campbell and James Ferguson-Lees (Constable, 1972) or A Field Guide to the Nests, Eggs and Nestlings of British and European Birds, by Colin Harrison (Collins, 1975). Wrens can, however, sometimes take over other birds nests as a base for their own, and The Birds of the Western Palearctic (Volume V, edited by Stanley Cramp, Oxford University Press, 1988) reports that recently fledged young Wrens roost in a disused nest of another species, with the female sometimes feeding them in that nest: I wonder if this was what was happening here. Since the nest was not found early in the breeding cycle, we shall never know ...
A pair of Grey Wagtails Motacilla cinerea have been nesting on the rock face of flooded caves at a site in Wales for several years. They have often chosen ledges that have been impossible to reach safely, but in 2004, a nest was built at chest height near the entrance of the not-flooded part of one of the caves, and the female allowed daily monitoring. The following sequence shows, first, the female sitting tight on the nest:
next, the female sitting high - probably on newly hatched young:
the downy, blind chicks two days later:
and finally the chicks with their eyes open and feathers 'in pin', the perfect age for ringing:
Many passerines look quite similar when they are half-grown chicks, the differences between species only becoming apparent as their plumage develops, the bills and legs take shape, and so on. This similarity is illustrated by the following brood of four Spotted Flycatchers Muscicapa striata:
This was one of nine broods ringed this year within a mile or so of one Welsh village, an excellent performance from a species on the Red List of species of conservation concern, whose British breeding population has declined by 80% in the last 25 years.
Those who are interested in non-passerine nests and chicks can click here to go to Nest miscellany I - non-passerines.
Compiled by David Norman, with special thanks to Nicola Edmonds for all of the photographs except the first two, from nests in Wales.