Nest miscellany I - non-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 non-passerines.
Species using nest-boxes, specially provided for them, take little effort to find, but it still can be a big job to check them all. MRG now monitors several hundreds of large nest-boxes, many designed for Barn Owls Tyto alba and Kestrels Falco tinnunculus. Kestrel in the UK is on the Amber List of species of conservation concern, their population having declined by over one quarter in the last 25 years. As with the brood of Peregrines featured in May 2004, the chicks' bulging crops indicated that the adults were having little difficulty in finding food, in this case small mammals. Indeed, our visit had interrupted the meal of one of the chicks, on the right in the photo below, who was still swallowing a vole, with its tail protruding from its gape:
The visit to the same site in 2003 also yielded four healthy chicks ripe for ringing, but at a more advanced state of growth, with wing and tail feathers emerging:
The chicks of all diurnal raptors go through two downy plumages before becoming feathered, the first stage almost always being much whiter than the later plumage, which tends to be more creamy or grey in colour. Chicks are a suitable age for ringing when they have acquired their 'second down' plumage.
Another user of large nest-boxes is Stock Dove Columba oenas, indeed more of the boxes designed for Barn Owls are occupied by the doves than by the target species. Stock Dove chicks, in human eyes at least, would not win any beauty competition, and we should all be grateful that the world wide web does not (yet) include transmission of smell:
The chicks of most waterbirds develop slowly, and we ring very few, but they often provide quite complete nest records from nest-building to eggs to chicks and fledging. Coot Fulica atra is a typical example:
Most Mute Swans Cygnus olor are ringed by members of the specialist study groups, such as the Cheshire Swan Study Group and the North West Swan Study Group. Again, MRG members record quite a few nests annually. Both members of the pair are usually close to the nest, as in the images below where the female guards the seven recently-hatched cygnets and the male stations himself to intercept any human approach to their very public nest site, although he pretends to be feeding!
The typical nidifugous (altricial) species, such as waders and terns, have well-developed tarsi that are almost full-size (in diameter) from the moment they emerge from the egg. This has evolved to facilitate the chicks' movement, but is also highly convenient for ringers, meaning that chicks can be ringed and their progress followed almost from the moment that they hatch. The chicks of nidifugous ground-nesting birds have evolved to be well camouflaged in their typical habitats, and they usually crouch and rely on their cryptic plumage to evade detection.
Oystercatchers Haematopus ostralegus have increased in numbers and spread away from their original coastal areas. It is quite easy to tell when their eggs have hatched by the change in behaviour of the adults:
This picture nicely shows the shorter and deeper bill of the male, on the right, that was referred to in an earlier photo-discussion on these pages. Like all nidifugous species, the chicks are well camouflaged. They are present almost in the centre of the next photo: take a moment to try to spot them before scrolling down to the next image!
The position of the rocks and stones can be used to pinpoint them in the above photo. These chicks are about five or six days old.
Little Ringed Plovers Charadrius dubius are specially protected on Schedule 1 of the Wildlife and Countryside Act 1981. Their nests are well camouflaged, and the chicks' cryptic plumage similarly helps them to blend into the background. The three chicks, in their nest-scrape, are visible in this first photograph (if you know where to look!):
whilst a 'medium distance' view shows how well they blend in to the lichen-covered stones at this site:
and a close-up picture reveals their delicate patterning and gentle appearance:
Little Tern Sterna albifrons, also a Schedule 1 species, nests in one colony in our area and I have been studying them since 1983, including weighing and measuring the chicks and plotting their growth rates (D Norman, ‘The growth rate of Little Tern Sterna albifrons chicks’, Ringing & Migration 13 (1992) 98-102). The chicks' growth is a good measure of how well the adults are finding food and hence an important conservation tool for monitoring the health of their fishing grounds. Little Tern chicks develop more quickly than almost any other non-passerine. This series of five photos shows birds from recently hatched (less than one day old), with the third egg pipping:
to three days old:
to six days old:
to thirteen days old:
and finally, about 16 days old, at which age the chicks can already fly some distance, but sometimes 'forget' and still try to rely on their camouflage:
Those who are interested in passerine nests and chicks can click here to go to Nest miscellany II - passerines.