Tuesday, 29 May 2012

Answer from Poland

I received an answer from the Polish Ringing Center about their HN-45088 Common Tern, caught on 6th May at Atlit salt pans. This bird was ringed as pullus in summer 2008 near Warsaw by A. Olszewski. The distance between the ringing site in Poland and the recapture site in Israel is 2464 km (see map). This is the first Polish control of Common Tern in Israel, and only second spring control, the other was from Ukraine (1984). I fitted this bird with a white plastic ring with black code I76 and I hope it will be resighted again in Poland or perhaps in winter in Africa.

Monday, 28 May 2012

Breeding season

Last Sunday I visited my CES; numbers of juveniles are going up- many Reed Warblers, Sardinian Warblers, Graceful Prinias and one juvenile Blackbird. I had still some late migrants, Great Reed Warbler, Sedge Warbler, Marsh Warbler and Blackcaps.

Juvenile Reed Warbler

In Atlit we caught 25 birds: 18 Common Terns, 6 Little Terns and one Little Stint. In this period tern migration is over and the breeding population is too busy. I will return to ring them when the chicks fledge in a few weeks.

Common Tern

Monday, 7 May 2012

Terns on the move

Another successful night at Atlit saltpans (6-7/5) produced 111 birds caught. Most interesting was Common Tern with the ring: HN 45.088 ST.ORN.GDANSK POLAND. This is the fourth foreign control since I started my tern project in 2010 and first in spring migration, joining Finnish, Lithuanian and German Common Terns caught in this place. Totals were 105 Common Terns, including retrap from last year, only 3 Little Terns, 1 Ruff and 1 Little Stint.

After I ended my ringing session in the morning I received a call from Tuvia Khan who had just observed three of my Little Terns at Ma'ayan Tzvi fishponds, 12.5 km south. One ringed in August 2010, one in June 2011 and to my surprise one from this night. Interesting info kept coming in; was continue when I arrived back to my computer I saw another report of two ringed Common Terns observed and photographed in Hula Nature Reserve by Dror Galili. IIF was ringed in August 2010 and IT3 ringed in June 2011, both from Atlit, 76 km south west. Very interesting data about their movement inside Israel.



This night I ended all possible combinations for white plastic rings and started work with green rings for Common Terns.

Another note from this night: we caught many Common Terns with dark bill. I don't know what the explanation for this is; perhaps only regular variation within our local breeding population or geographical variation among migrant birds.

Little Tern

Many thanks to my team: Rafi, Ron, Eilai, Yishai and Shachar.

Short ringing session in Tzor'a on Friday produces 120 birds; first fledglings of Clamorous-reed and Cetti's Warblers were ringed. Also I ringed this juvenile Whitethroat with active partial moult - first sign of the upcoming autumn?

Juvenile Whitethroat - active partial moult

Thursday, 3 May 2012

First tern ringing - putative White-cheeked Tern

After eight months without terns I visited Atlit Saltpans for ringing. The first night of this season (29-30 April) was a complete success with 64 birds caught; 60 Common Terns including one retrap from last year, 1 putative White-cheeked Tern, 1 Little Tern, 1 Slender-billed Gull and 1 Little Stint.
The putative White-cheeked Tern is 2nd calendar bird with typical primary moult and winter / non-breeding-like plumage. The main features pro White-cheeked Tern are a grey rump, uppertail and tail rectrices without contrast to mantle colour; in Common Tern there is a clear contrast between the grey mantle and white rump (see image).

Putative White-cheeked Tern

Second feature is larger tail / wing ratio (longer tail, shorter wing). Tail length was 169 mm, the longest tail I have measured (n=387). The wing/tail ratio is 1.60 - a very low figure, lower than the normal range of 1.62-2.85, average 2.00 (n=386); in 2nd calendar birds (n=10) the range is slightly higher, 1.93-2.75, so this bird has a really exceptional wing / tail ratio.
Another aspect of wing/tail ratio is the distance between wingtip and tail; in this bird the tail is long than the wing. In other birds caught this night (all adults) the wing was longer.

Other measurements:
Wing=270 mm
Tail=169 mm
Fork=85 mm
Bill(s)=43.5 mm
Bill(f)=35.2 mm
Tarsus=22.5 mm

In the past, this subject was discussed after I caught terns with rump as White-cheeked and dark underparts. But this possibility was overruled after images of mating Common Tern X 'like White-cheeked' Tern in my ringing region were posted. This bird look better for a genuine White-cheeked Tern, especially the tail pattern. This species breeding in the Red-Sea and Indian Ocean is little known, especially in respect to the amount of variation of these features in young birds. I searched for information about identification and found only a short article from 1982 (Dutch Birding). I will be glad to receive some information or ideas, especially biometrics.

Regular Common Tern

Thanks to Avishai, Rafi and Eilai for their help this night.