Saturday, 12 May 2012

European Nightjar in the UAE.

The European Nightjar (Caprimulgus europaeus) is a fairly common spring (April & May, rarely June) & autumn passage migrant (September to November) and  rare winter visitor.

European Nightjar at Al Wathba Camel Racetrack.

 It breeds to the north of the UAE in a huge tract of country, extending from western Europe, through Russia, Kazakstan & even as far east, as northern Mongolia & around Lake Baikal in Siberia. The only known wintering grounds are in sub-saharan Africa, with many individuals migrating as far south as southern Africa. However, it is perfectly possible that his species could winter in small numbers in southern Arabia & indeed, in remote Sudan. There are few observers in such places & it is an inconspicious species, which is easy to miss. The few winter records in the relatively well watched UAE would support this theory.

Taken from de Hoyo et al 1991.

Recent research has shown that this species may have a wider wintering distribution than previously thought. With birds not necessarily migrating due south from their breeding grounds. It came as quite a shock to discover that breeding birds from southern England  wintered in the hitherto unknown area of the Democratic Republic of Congo and not as presumed in west Africa. This is south-east of their breeding grounds & not due south.

Notice the slight differences in the wintering distribution of European Nightjar in the two maps. This underlines the lack of present knowledge of the wintering grounds of this species, in areas where there are few observers. certainly in the relatively well watched South Africa it ia a common wintering bird in miombo woodland and all types of savannas. It may also turn up in parks and large gardens, often returning to the same tree to winter each year.

One individual in my garden in South Africa
 came back to the same tree (even the same branch)
 for three consecutive winters)!
A remarkable incidence of site fidelity!

There are at least six, currently recognised races of European Nightjar, several of which pass through the UAE. However, these races are not always clear to identify in the field, as plumage tones and features tend to be clinal, as one so called race, slowly merges into another race.

Caprimulgus e. europaeus - this is the large dark, grey toned nightjar that we are familiar with in the UK. However, once you go east, birds start to get greyer plumaged tones and as you travel south they slowly get smaller.

Caprimulgus e. meridionalis - greyer, than the nominate form above. Males having even larger white spots on the primaries than the nominate. However, variation is very clinal & some authorities have questioned the validity of this form.

Caprimulgus e. sarudnyi - greyer than nominate in the est of its range becoming buffier brown in the more eastern parts. The male has huge white spots on the primaries and whiter/buffier undertail coverts, which may be seen when the bird is at rest in a tree, or bush. Intergrades with the nominate form and probably with the next form as well.

Caprimulgus e. unwini - smaller, paler & greyer than the nominate and on average, slightly smaller than sarudnyi. This form may have conspicuous white patches on the sides of the throat and a paler hind collar. Very sparesely marked undertail coverts, seen when at rest. The male has large white spots on the primaries (larger than nominate).

Caprimulgus e. plumipes - this is a large pale, nightjar, with huge white spots on the primaries. Tends to look sandy all over.

Caprimulgus e. dementievi - much more vermiculated than the central Asian races. Of uncertain validity.

It is unlikely that the form meridionalis occurs in the UAE on passage, due to the UAE being slightly to the east of it known breeding range. Without catching the bird it would be almost impossible to prove this race, as features and plumage tones are clinal with the nominate europaeus.

Caprimulgus e. dementievi could occur on passage, but again how would you identidy it with certainty without a specimen?

The nominate form europaeus, certainly occurs in good numbers, with over 70% of all birds on passage, in the UAE, being of this race. However, clinal tones of plumage, complicate the situation.

Caprimulgus e. sarudnyi & unwini occur on passage, but are difficult to tell from each other. However, they are readily recognisable from the nominte form.

Caprimulgus e. plumipes almost certainly occurs on passage, but I haven't seen any birds, which look like this race.

The European Nightjars on passage in the UAE fall into two groups:

the large dark, well vermiculated nominate form

the paler often greyer or sandier, slightly smaller less vermiculated,sarudnyi/ unwini types.

Both these types may be seen on the same days on passge. Although, all the earlier birds, tend to be of the europaeus type. This is to be expected, as if one looks at their breeding distribution all three forms are directly to the north of us.

Caprimulgus e. europaeus - ranges from western Europe eastwards to Lake Baikal area. This is a tremendously large breeding range & it is locally common within this range.

Caprimulgus e. sarudnyi - Kazakhstan, eastwards to the Altai Mountains.

Caprimulgus e. unwini -  Iraq & Iran, east to Pakistan.

All these forms, winter in east and southern Africa and pass directly over Arabia on their long distance migrations.

A selection of European Nightjars
 taken in South Africa.

Caprimulgus e. europaeus - in western Europe, this is a large, dark, very well vermiculated nightjar. The white primary spots of the male are rather restricted. But as you move eastwards birds have generally greyer plumage tones, but they are still the most vermiculated of all the forms found in the UAE. May show slighlty paler hind neck collar.

Caprimulgus e. europaeus - of the smaller, greyer variety.
Still very well vermiculated though.
Photo courtesy of Huw Roberts.

Caprimulgus e. sarudnyi - overall, this race is smaller then the nominate form. But it still looks quite large! When you flush a bird of this race, you see a large pale nightjar, with very extensive primary wing spots (males only) and broad white tail corners. At rest from below the tail may look like a band as in crested Honey Buzzard! This race may be grey or more sandy in general plumage tones & has less vermiculations than the nominate form.

Possibly Caprimulgus e. sarudnyi
Photo courtesy of Huw Roberts.
 Caprimulgus e. unwini -generally, the smallest of all the races found here. Looks pale, sandy and less vermiculated. A very small, plain looking nightjar, but with extensive wing & tail spots in the males. Look for large white areas at the sides of the throat when perched and virtually unmarked undertail coverts. Some birds may not be separable from sarudnyi, as features & size are clinal. These latter two races, arrive later, in late April/May than the nominate, which tends to peak slightly earlier.

Caprimulgus e. unwini? - female.

Caprimulgus e. unwini
Photo courtesy of Huw Roberts.

In southern Africa, where this species is common from October through to late February, all of the above races have been identified (often from road kills). A small number of individuals arrive in September, which is very early for so far south. Do some birds not complete their entire migration to their normal breeding grounds?

European Nightjar passage through the UAE is very strong in spring, but more protracted & less noticeable in autumn. Many must pass through unnoticed on the mainland. It is only when one visits isolated, little vegetated islands, that you realise how common this species can actually be.

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