With its colourful plumage and distinctive song, the chaffinch is the bird that is most commonly seen and heard in the Caledonian Forest.
The chaffinch occurs throughout all of Europe and western Asia, including Russia, Georgia, Armenia, Azerbaijan, Turkey and northern Iran. It also occurs in northwest Africa, in Morocco, Algeria and western Tunisia, and in the Macaronesian Islands, where there is an endemic subspecies in each of Madeira and the Azores, and three subspecies in the Canary Islands. It has been introduced from Britain to New Zealand, where it has become well-established, and to South Africa, where there is a small population near Cape Town.
Distribution in Scotland
The chaffinch is common and widespread throughout Scotland, except in the largely treeless areas of some of the remoter islands, such as the Outer Hebrides and Shetland, where it is scarce or absent. It occurs wherever there are bushes, scrub or woodland, and is found in gardens, hedgerows and town parks. It is the commonest bird in the Caledonian Forest, living in both Scots pine- and birch-dominated areas, and has also adapted to live in conifer plantations.
The chaffinch is resident year-round and breeds in Scotland. The UK population has been estimated at about 6 million pairs, and in winter this is boosted by birds, often predominantly females, which migrate southwards from Scandinavia. The chaffinch’s specific name ‘coelebs’ means ‘bachelor’ and was given to it based on the observation in Sweden that the males stayed there over the winter, while the females moved south.
With its wide geographic range, large population size and stable numbers, the chaffinch is not at risk at all, and in the IUCN Red List of Threatened Species it is classified as ‘Least Concern’, meaning that it is at the lowest risk of extinction.
Physical characteristics and behaviour
The chaffinch is a sparrow-sized bird in the finch family Fringillidae, in the order Passeriformes, which is the taxonomic category that covers perching birds (more than half of all bird species). An adult chaffinch is 14 -16 cm. in length, with a wingspan of up to 28 cm., and weighs 20 – 25 gm.
Like most finches, it features sexual dimorphism, meaning that the male and female have clear physical differences, which in the case of the chaffinch take the form of distinct colour variation between the sexes. The male is more brightly-coloured than the female, with reddish-orange underparts and cheeks, blue-grey on the top of the head and back of the neck, a green rump and double white bars on the wings, which are visible both when it is at rest and in flight. The female is duller overall, with the body being mainly greenish-brown, but the double white wing bars are similar to those on the male. The plumage of the male becomes brighter in spring, for the breeding season, and after moulting in early autumn it is paler throughout the winter until the following spring. Both the male and female have a short, thick, conical beak.
The average lifespan of the chaffinch is estimated at 3 years, although individuals have been known to live to a maximum of 12 or even 14 years. The song of the male chaffinch is one of the most distinctive of all bird songs in the UK and consists of a series of sharp, quick notes followed by a flourish at the end. It lasts for up to 5 seconds, and is often repeated constantly for a minute or more. The chaffinch also makes another call, consisting of a repeated trill, and this is known as the ‘rain call’, as in the past it was thought to foretell rain.
The main food of the chaffinch is seeds, although its diet also includes berries and fruits. The chicks are fed insects, especially caterpillars, and in the breeding season the adults also eat insects. In some places, including the visitor car parks in Glen Affric, chaffinches have become accustomed to being fed breadcrumbs by people, particularly in the spring. In winter, the chaffinch forms large feeding groups, sometimes in mixed flocks with the closely-related brambling (Fringilla montifringilla).
The male chaffinch establishes a breeding territory in February, usually returning to the same territory each year. The male sings and performs courtship displays to attract a female, and a pair will spend about six weeks together before breeding begins. Reproduction takes place in April and May, and the female builds the nest, which is usually sited in the fork of a tree or under dense foliage on a branch. It is cup-shaped, made out of moss, lichen and spider’s silk, and is superbly camouflaged, with lichen decorating the exterior.
The female lays 3 – 5 eggs, one per day, and they are pale greenish-blue in colour with purple speckled markings. Incubation is done by the female alone, and takes 11 – 14 days. After hatching, the chicks are fed in the nest by the female for about 12 – 16 days. Once the chicks leave the nest they stay nearby, and the male joins in with feeding them, for another 15 – 20 days, until they are able to feed for themselves. The chaffinch will raise either one or two broods per year. Experiments have shown that male chicks need to hear the song of adult males during a critical time period after hatching, in order to become proficient singers themselves when mature.
Ecological relationships of the chaffinch
As a mainly seed-eating bird the chaffinch has a negative effect on the ability of plants to reproduce, by consuming their seeds, but this rarely makes a significant difference, because of the volume of seed produced by most plants. However, in some cases its feeding behaviour is beneficial, for instance with the berries of the rowan tree (Sorbus aucuparia). When the chaffinch eats those, it digests the pulp of the berries, but the seeds pass through its gut unharmed and germinate where they are deposited in its droppings – often underneath where it perches, on the branches of old Scots pines (Pinus sylvestris).
Predators of the chaffinch include raptors such as the sparrowhawk (Accipiter nisus), goshawk (Accipiter gentilis), merlin (Falco columbarius) and tawny owl (Strix aluco). Chaffinches will engage in mobbing behaviour to discourage predators, for example if they see a tawny owl roosting in a tree during the day. The pine marten (Martes martes) will take both eggs and chicks if it finds a chaffinch nest. Unlike some other similar-sized birds, the chaffinch rarely suffers from brood parasitism by the common cuckoo (Cuculus canorus), whereby the cuckoo dupes an unsuspecting host bird into raising a cuckoo chick as though it was its own. This is possibly explained by the fact that chaffinches have been observed making an aggressive response to cuckoos that approach their nesting sites.
A number of ectoparasites, or external parasites, feed on the chaffinch, including fleas such as the European chicken flea (Ceratophyllus gallinae) and the moorhen flea (Dasypsyllus gallinulae), chewing lice (Menacanthus sp.) and three species of feather mites (Analges passerinus), (Monojoubertia microphylla) and (Pteronyssoides striatus). The larvae of a blood-sucking blowfly (Protocalliphorus sp.) have been found feeding on chaffinch chicks in the nest. The sheep or deer tick (Ixodes ricinus) also occurs on the chaffinch, and some birds have been recorded containing the bacterium (Borrelia burgdorferi) that causes Lyme disease, which is transmitted by the tick. Several species of intestinal parasites, or coccidia, in the genus Isospora and a blood parasite (Haemoproteus sp.) have been found in chaffinches. A virus known as Fringilla papillomavirus causes a wart-like growth on the legs of chaffinches, with the warts sometimes covering a whole leg.
Despite the attentions of predators and parasites the chaffinch population in the UK is thriving, and it is the second most abundant bird in the country. With its colourful plumage and distinctive song, it’s the most commonly seen, and heard, bird in the Caledonian Forest.
Alan Watson Featherstone
Illustration on this page by Henrietta Rose.
Sources and further reading
Dickson, RC. (2000 ) Merlins selectively preying on Chaffinches Scottish Birds, 21: 50.
Gryczyńska A, Dolnik O, Mazgajski TD. (1999) Parasites of Chaffinch (Fringilla coelebs) population. Part I. Coccidia (Protozoa, Apicomplexa). Wiad Parazytol. 45(4): 495-500.
Gryczynska A., Dolnik O., Pawelczyk A., Mazgajski T.D., Siemiatkowski M. (2000) Parasites and pathogenes in population of Chaffinch (Fringilla coelebs) from Masurian Lakeland (NE Poland) Acta Ornitologica Vol: 35, number: 1