Dutch Birding volume 23 (2001) no 4

Identification of Two-barred, Greenish, Bright-green and Arctic Warblers

Sonagrams and sound-clips of Two-barred Phylloscopus plumbeitarsus, Greenish P trochiloides viridanus, Bright-green P nitidus and Arctic Warblers P borealis. All sonagrams refer to normal contact calls, except when stated otherwise. Note variation in contact calls. In all sonagrams distances between calls have been shortened. Each call is treated individually. In the sound-clips presented here it was also sometimes necessary to shorten distances between calls to reduce the size of the files, but the extremely short distances used in the sonagrams would make for difficult listening. Sound-clips where the distances between calls have been altered are marked with a *. Where there is no * the timing is unaltered from the original recording. Sometimes there are several calls from a single sound-recording, and these have often been chosen from different parts of a recording. In most cases an affort has been made to illustrate the same calls in the same order both in the sound-clip and the sonagram. In three cases song was also included in the sound-clip to illustrate the context in which the calls were heard.

Two-barred Warbler / Swinhoes Boszanger Phylloscopus plumbeitarsus

a: Adult male, Sayan mountains, Tuva, south-central Siberia, Russia, July 1995 (Magnus S Robb)
b: Khao Yai, Thailand, 17 November 1991 (Arnoud B van den Berg)
c*: Khao Yai, Thailand, 20 November 1991 (Arnoud B van den Berg)
d: Khao Yai, Thailand, 20 November 1991 (Arnoud B van den Berg)
e*: Khao Yai, Thailand, 29 November 1991 (Arnoud B van den Berg). Includes some high, sharp, short calls which might be mistaken for Arctic Warbler P borealis
f: Khao Yai, Thailand, 29 November 1991 (Arnoud B van den Berg)

Greenish Warbler / Grauwe Fitis Phylloscopus trochiloides viridanus

a*: De Cocksdorp, Texel, Noord-Holland, Netherlands, 2 September 1999 (Roy Slaterus)
b: Probably juvenile male, IJmuiden, Velsen, Noord-Holland, Netherlands, 9 September 2000 (Magnus S Robb/The Sound Approach)
c: Chokpak Ornithological Station, Kazakhstan, 12 May 2000 (Magnus S Robb/The Sound Approach)
d*: Chokpak Ornithological Station, Kazakhstan, 12 May 2000 (Magnus S Robb/The Sound Approach)
e*: Near Bolshoe Almaty Lake, 32 km south of Almaty, Kazakhstan, 18 May 2000 (Magnus S Robb/The Sound Approach)

Bright-green Warbler / Groene Fitis Phylloscopus nitidus (Arnoud B van den Berg)

a*: 3 km south of Ikizdere, Rize, Turkey, altitude 1300 m, 13 May 1987. Note that a call proceeds each of the two song phrases
b*: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987
c: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987
d*: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987
e: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987

Arctic Warbler / Noordse Boszanger Phylloscopus borealis (Arnoud B van den Berg)

a: Bloemendaal, Noord-Holland, Netherlands, 9 September 1991. Call of trapped bird in cage
b: Bang Thieo, south-east of Krabi, Thailand, 11 May 1994
c: Kuala Selangor, Selangor, Malaysia, 19 October 1993
d: Ko Libong Island, west of Trang, Thailand, 18 March 1989. Variable calls given in context of 'plastic' or developmental song. Note that this sound-clip is a section of the original recording including song and illustrates a selection of calls similar but not identical to those in the sonagram.

Sonagrams and sound-clips of 'thin calls' of Bright-green P nitidus, Arctic P borealis, Greenish P trochiloides viridanus and Two-barred Warblers P plumbeitarsus. 'Thin calls' can be given in several contexts. Note variation. In all sonagrams distances between calls have been shortened

Bright-green Warbler / Groene Fitis Phylloscopus nitidus
a: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987 (Arnoud B van den Berg). Alarm calls
b: 7 km north of Ikizdere, Rize, Turkey, altitude 1000 m, 14 May 1987 (Arnoud B van den Berg). Alarm calls

Arctic Warbler / Noordse Boszanger Phylloscopus borealis
c: Ko Libong Island, west of Trang, Thailand, 18 March 1989 (Arnoud B van den Berg). Calls given in context of 'plastic' or developmental song

Greenish Warbler / Grauwe Fitis Phylloscopus trochiloides viridanus
d: Adult male, Chokpak Ornithological Station, Kazakhstan, 12 May 2000 (Magnus S Robb/The Sound Approach). Calls given during song bout

Two-barred Warbler / Swinhoes Boszanger Phylloscopus plumbeitarsus
e: Cat Tien, Vietnam, 16 January 1998 (Edward Vercruysse)

Comments, sonagrams and preparation of sound clips by Magnus S Robb, André J van Loon and Arnoud B van den Berg.