Reported - White-winged Gulls

Andrew Chick · **Posted:** Tue Mar 24, 2009 7:57 pm

Reported

Crosby landfill site - 24th March 2009

2 Iceland Gull - both reported as juv but I guess that they must be 1st Winter??
1 Glaucous Gull - again reported as a juv, but assume is 1st Winter??

blgp_birder · **Posted:** Wed Mar 25, 2009 7:08 pm

Hi Andy - white-winged gulls in their "first winter" (i.e. 1st and in to 2nd calendar years) are juveniles, due to the fact they retain juvenile plumage.

Andrew Chick · **Posted:** Wed Mar 25, 2009 8:21 pm

Interesting comment (and you may be right......) - my copy of Gulls of Europe, Asia and N America shows separate Iceland Gull illustrations for Juveniles/1st Winter (Aug-Apr) and then 1st Winter (Feb-May) and for Glaucous Gull describes 'Late' 1st Winter (Mar-Aug).
The only difference is feather wear because you are correct that they don't moult - but at the end of March to suggest that a Gull that was born in May last year is still a juvenile can't also be right? So, maybe we could meet halfway and call them 1st Year birds?
I only reported these birds and didn't see them myself, I have no idea if the record is genuine, it did appear on birdguides - but that isn't always 100% as there is little effort to verify this type of record....
Andrew

Stuart Britton · **Posted:** Wed Mar 25, 2009 10:01 pm

I think you are both half right! White winged gulls do retain juvenile plumage in to their second year which is easy to distinguish in the field. In the case of Greater black backed Gulls it is possible to accurately age 4th winter birds by the pale brown streaks on the outer primary coverts which are technically juvenile feathers. I think a more appropriate term at this time of year would be "immature". I suspect Ed Mackrill would be able to clarify this.

blgp_birder · **Posted:** Wed Mar 25, 2009 10:17 pm

Stuart Britton wrote:

In the case of Greater black backed Gulls it is possible to accurately age 4th winter birds by the pale brown streaks on the outer primary coverts which are technically juvenile feathers.

Technically they won't be juvenile feathers as they won't have been retained since they were born!

The most appropriate term is "juvenile" for Glaucous and Iceland Gulls as they only have a juvenile plumage. "Immature" refers to any birds which are not adults, so isn't exactly appropriate for accurately labelling 1CY/2CY white-winged gulls.

The first-winter bit will probably refer to the fact that the bird is in its first winter (chronologically-speaking). Calling them first-year birds is also a little inaccurate, best thing to do with these birds in their first spring/summers is label them 2nd calendar-years (2CY)! The reason Iceland and Glaucous Gulls often end up looking so messy in their first summer is down to the fact that they have retained the same set of feathers they were born with throughout their whole first year.

What complicates the issue is that we now know Thayer's Gulls can have a genuine 1st-winter plumage (scapular moult being most notable here). The 2005 Mayo bird was treated as a tad suspect before this was more widely-known..

The initial report apparently came from BirdNet as far as I can see; as for verifying the report there is not alot that can be done without actually going to the site but as both species are straightforward to identify I imagine there will be little problem with the record.

Josh

Andrew Chick · **Posted:** Wed Mar 25, 2009 10:38 pm

Well I am happy with 2nd calendar-years (2CY) birds - :lol:

although if I was ringing one, I would be calling it a 5....

Regarding verification of the record - I guess without a photo or someones (real) name attached to this record it will just be ignored and forgotten.... shame really!

Andrew

blgp_birder · **Posted:** Wed Mar 25, 2009 11:50 pm

Does anyone local watch the tip then? If its attracted three wingers surely it must be worth a bash for anyone in the area?

John T Goy · **Joined:** Tue Dec 28, 2004 11:30 pm **Posts:** 2385

I'd be interested to know where Crosby Landfill is, that's a new one on me and it comes within my local patch.

Could they be referring to Crosby Warren?

Max

Colin and Sheila Jennings · **Posted:** Mon Mar 30, 2009 4:37 pm

Reported by Phil Lee - aka - Nottsbirder

It was me who saw and reported the gulls.

You are all correct there was 2 x 1st winter Iceland and 1 x 1st winter
Glaucous.
One of the Icelands was visibly paler than the other but I thought it was
still a 1st winter.

I viewed them looking towards Crosby landfill site
with the sun behind me at a place that is not accessible to the general
public.

This is much better than nearby Bagmoor where you stand facing the sun.

The birds where seen in just a 20min spell and there where literally 100's
of gulls present.

Also on your website you have the much debated topic of Goshawks.

I too have seen juv Goshawk in Lincs.
It was in March last year on the edge of Misson Carr NR which is mostly in
Notts but the NE corner is just in Lincs.

John T Goy · **Joined:** Tue Dec 28, 2004 11:30 pm **Posts:** 2385

It may be better than Bagmoor but as you say it is PRIVATE, so actually it isn't unless that person works for Corus!

Max

The Lincolnshire Bird Club

Reported - White-winged Gulls

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