Biology

Background
In 1977 in his book Birds of Norfolk, Michael Seago wrote about the Golden Oriole,  "an almost annual spring migrant in very small numbers; occasional in autumn. There is no satisfactory evidence of breeding". In 1999, he wrote with others, in the 'new' Birds of Norfolk "A very scarce summer visitor and spring passage migrant; rare in autumn". Peter Dolton a Golden Oriole Group member who has studied the birds for many years compiled the report. He describes the dates and areas where the birds have been seen and has produced a table of the number of confirmed breeding pairs and number of other potential breeding sites from 1985-98. Peter mentions that Golden Orioles are very reliant on poplar trees, mostly hybrid Black Poplars Populus nigra, where every nest found in Norfolk has been in one. Because the nests are high in the canopy they are not easily seen from the ground. As a result it is difficult to prove that the birds have actually breed. Another source of information on Golden Orioles was produced by the BTO in Bird Study Vol.45, Part 3, November 1998. The Breeding Biology of the Golden Oriole was written by Digby Millwright also from the GOG, which explains the arrival sequence of the males and the dates that the females arrive at their chosen breeding areas, when they sing and how they perform their display flights. Since then an important gathering of information on UK birds is the collation by Chris Mead in his 'State of the Nations Birds' produced in 2000. He mentions the colonisation to East Anglia from the continent about 30 years ago of Orioles, probably from Holland, with a population increase up to a possible 42 in 1990, then, to his final sentence, "Here to stay and, with the help of global warming, to spread"?

The real story is quite different. Since 1990 a decline has taken place.The sightings are definitely fewer; the opportunities for study less, coupled with the frustration of not being able to see these birds around the viewing points where they used to go with regularity. Indeed the Chairman of the GOG reported in his annual appraisal to say that "2001 has been the worst year [for Orioles] since the GOG’s inception in 1986”. It is for this reason that we are appealing to birdwatchers, especially in East Anglia, to report any sightings or song of Golden Orioles (especially inland sightings) to us as soon as possible, so that a Golden Oriole Group member can react quickly to establish whether the bird has come to breed.

Here are some refreshers for your memory and hopefully they will stimulate the desire to go out and find some birds.

Arrival
Spring migration is late; vacates winter quarters March-April, and returns to breeding grounds late April to May, when the trees come into leaf. The male returns first around 14 May; female follows about 7 days after, depending on weather.

Field characters.
Description: A rather large, length 24-25 cm; colourful passerine, with a strong dark pink bill, long wings, giving a wingspan 44-47 cm. and quite long tail; shape on perch recalls Starling, shape and actions in flight suggest large thrush (Mistle) or woodpecker. About 15% larger than the Starling, with proportionately longer wings and tail producing a shape rather like a Mistle Thrush;  smaller than the Green Woodpecker with which it can be confused, especially the female. Male is unmistakable; plumage bright yellow with black lores, wings, and tail; the tips of outer tail feathers are yellow. Female and juvenile rather similar, although former is more brightly coloured: upperparts, flanks and vent greenish yellow, wings and tail darker and greener; remaining underparts white with a faint yellow wash and finely streaked with grey. More often heard than seen, since the bird is very secretive and prefers to remain hidden in canopy.

Flight fast, heavy and gently undulating, woodpecker-like. Most often seen alone or in pairs, but sometimes in flocks on migration.

Voice: Highly characteristic: Common call a liquid, rather melancholy, but fast and clear beautifully modulated fluting whistling "weela-weeow". When alarmed it utters a harsh, Jay-like, scolding "skaah", or a harsh cat-like squall and rattling notes.

Distribution: A fairly common breeding bird in entire Europe, except Great Britain and Scandinavia, where it is scarce and local. It breeds from southern England and Iberia eastwards across Eurasia to the Altai mountains and India, and from southern Finland and Russia in the north to northwest Africa, Iran and India in the south. Birds of the nominate race breed across all but the southeasternmost part of the range and winter in sub-Saharan Africa.

Habitat: A strictly arboreal bird, which prefers the canopy of predominantly deciduous trees in well-wooded regions. Recently mostly confined to the fenland basin of East Anglia, but not exclusively so. The European breeding population of between one and five million pairs is widespread, and occurs mainly in deciduous woodland; in the north (notably in Belgium and the Netherlands) in damp poplar or alder woodlands and plantations near water and in the south, in a wide diversity of woodlands including oak woods, shelter belts, orchards, parks and gardens.

Food: Predominantly insects, e.g. caterpillars and mostly bumble bees, but in late summer also considerable quantities of fruit. To find out more on the diet of Golden Oriole click here