Sonogram of the Lieksa bird on 6th June 2001, same as the recording 1.
compiled by Antero Lindholm
The first two Oriental Cuckoos (Cuculus saturatus) in Finland were observed in June 1998, at Karstula and at Lieksa. The next year both birds were back and there was one additional individual, at Joutsa. In 2000 and 2001 only the Lieksa individual returned. Some discussion about (mostly) the Lieksa bird follows. A more complete text will be published later and it will cover some more characters with potential relevance in identification (here is the most important, in my current opinion) as well as proper literature references, material and background data, acknowledgements etc.
Little by little it became evident that the song of the Finnish birds was subtly but clearly different from what was known as Oriental Cuckoo song. The northern horsfeldi (sub)species of Oriental Cuckoo should have a song pu-pu, both syllabless of the same or almost same frequency.
The Finnish birds (probably all of them) have uttered two- or (more often) three syllables up-PU-PU. The second syllable is slightly higher than third. The first is shorter and weaker, it is not easily heard from a distance and is sometimes lacking altogether. Because the slightly higher second syllable made the song slightly more similar to the song of European Cuckoo Cuculus canorus, we became worried. In addition, several consulted experts had difficulties accepting the recordings as Oriental Cuckoo.
Listen song 1, size 108 kb, wav-format,
Finland, Lieksa 06.06.2001, copyright (c) Antero Lindholm. Undoubtly the same
individual as in the pictures.
Listen song 2, size 97 kb, wav-format,
Finland, Lieksa 25.05.2000, copyright (c) Ari Rajasärkkä. Same place, different year.
Listen song 3, size 246 kb, wav-format,
Russia, Komi Republic, Near Syktyvkar, June 2002, copyright (c) Antero Lindholm. "Typical" Oriental Cuckoo call for comparison.
Sonogram of the Lieksa bird on 6th June 2001, same as the recording 1.
The Lieksa individual was trapped and studied on 6th June 2001 to
get more documentation. The following photos were taken by Osmo Huupponen and
Antero Lindholm. They were taken at midnight and are therefore not technically
perfect, using a video camera without the help of artificial light, but it was a
fine night with a full moon. There are also some comparison photos of Cuckoo,
taken at Rautalampi by Osmo Huupponen and Antero Lindholm, and some of skins at
The Finnish Museum of Natural History by Antero Lindholm. The bird at Lieksa in
1998 and the 2001 individual are very similar and probably the same bird – as
would be expected. There are also photos of the 1998 bird in the article by
Heikki Vasamies in Alula 3/1998 and also at
http://www.jmp.fi/~pslty/kuvagalleria/idankaki.jpg.
Picture 1. Underwing of the Lieksa bird.
Picture 2. Underwing of the Lieksa bird.
Note the buffish tone on the flanks and some of the underwing-coverts which
would be unusual in European Cuckoo. The greater coverts are quite pale and
indistinctly barred and the bases of secondaries widely white (some out-of-order
coverts emphasise this). Note the very weak and in some areas non-existent
barring on the lesser coverts.
Picture 3. Underwing of adult male European Cuckoo, at Rautalampi, Finland on
3rd June 2001.
Superficially quite similar to the Lieksa bird. The length of the white
midwing-panel cannot be used as an identification feature because it commonly
continues to P7 in Common Cuckoo as well and sometimes even to P8. The width of
the panel is probably a more useful character (broader in Oriental) as are the
whitish, almost unpatterned foremost lesser coverts and the less patterned and
paler innermost greater coverts of Oriental Cuckoo. The greater coverts of
European Cuckoo can be almost unpatterned grey or distinctly barred as in this
individual. Note that the foremost lesser coverts are paler in this European
Cuckoo too, but completely barred. The undertail-coverts and vent of this
individual are buffish but the flanks and underwing-coverts are not.
Picture 4. Underside of the Lieksa bird.
Contrastically buffish undertail-coverts and vent, more buffish than most
European Cuckoos, but some come close. In this bird, the black bars on the
underside are not wider than is typical in European Cuckoo, nor are those on the
undertail-coverts . Very wide dark bars, almost as wide as the pale bars in
between, are possibly diagnostic for Oriental Cuckoo but does not occur in all
individuals, nor in this bird.
Picture 5. Underside of the European Cuckoos.
It is quite common European Cuckoos to show buffish undertail-coverts and
vent as these adult male European Cuckoos from Finland indicate. In some other
populations the colouration of these parts apparently is a good field character.
Picture 6. Marginal coverts at the wrist of the wing of the Lieksa bird.
Mostly whitish, only some darker smudges on the distal part (the image of
black bars on the proximal part of the area is created by unnaturally positioned
and moist feathers).
Picture 7. Marginal coverts of the European Cuckoo.
Normally the marginal coverts at the wrist of the wing are barred on Eurasian
Cuckoo, at least the inner parts, but the outer part which is sometimes visible
in field conditions, is more commonly white in European Cuckoo as well. This
adult female European Cuckoo from Finland is one of the whitest I have seen.
Picture 8. Head and bill of the Lieksa bird.
The bill is said to be thicker and shorter in Oriental Cuckoo. Bill dimensions for this bird were clearly within the variation of European Cuckoo. The bill length / depth – ratio was even slightly larger than majority of European Cuckoos indicating a quite long and/or thin bill.
Comments on call and other characters are welcome. Is it possible to identify this bird as Oriental Cuckoo beyond doubt?
Please send comments to the chairman of Finnish Rarities Committee, Visa Rauste (email: visa.rauste@helsinki.fi).
