Yellow H.501 back in Leiden again – 20130728

I have been expecting it for a little while now and today that expectation came true: Lesser Black-backed Gull Yellow H.501 has returned to Leiden again.

Its arrival is slightly later than last year (when my first observation was on July 17), which I’m sure the other local gulls won’t be sorry about because unfortunately for them H.501 is still as unfriendly as ever.

Not one to befriend easily: Yellow H.501 does not tolerate other gulls to be nearby very much. Leiden, The Netherlands, 28 July 2013.

Not one to befriend easily: Yellow H.501 does not tolerate other gulls in its vicinity. Leiden, The Netherlands, 28 July 2013.

Not one to befriend easily: Yellow H.501 does not tolerate other gulls to be nearby very much. Leiden, The Netherlands, 28 July 2013.

Not one to befriend easily: Yellow H.501 does not tolerate other gulls in its vicinity. Leiden, The Netherlands, 28 July 2013.

Yellow H.501 long-calling and spreading its wings aggressively. Leiden, The Netherlands, 28 July 2013.

Yellow H.501 long-calling while assuming an aggressive posture. Leiden, The Netherlands, 28 July 2013.

Yellow H.501 long-calling. Leiden, The Netherlands, 28 July 2013.

Yellow H.501 long-calling. Leiden, The Netherlands, 28 July 2013.

Wing moult

H.501 spends several weeks in Leiden shortly before and after the breeding season. During the post-breeding period, it waits until the primary moult is almost completed before moving on to the wintering location. Based on observations of the previous years, H.501 will stay here until the second or third week of October.

My last observation of H.501 was on 5 April 2013, 114 days ago.

Primary moult: P1 and P2 fully grown, P3 3/4 grown, P4 half grown, P5 dropped, P6 - P10 old. Moult score: 18 (5543100000). Leiden, The Netherlands, 28 July 2013.

Primary moult: P1 and P2 fully grown, P3 3/4 grown, P4 half grown, P5 dropped, P6 – P10 old. Moult score: 18 (5543100000). Leiden, The Netherlands, 28 July 2013.

See also:
Do adult Lesser Black-backed Gulls pair up in August?
Gulls that are only observed during the migration period
Lesser Black-backed Gull returns to my local patch for 4th consecutive year.

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5 thoughts on “Yellow H.501 back in Leiden again – 20130728

  1. This one seems like a very dominant gull. But I don’t know much about social structure of (non breeding) gull flocks. It’s something I’ve tried to find out about, but I don’t know if it’s ever been studied properly. I’ve never found anything about it, anyway.

    e.g. do the other gulls consider the most dominant bird to be ‘flock leader’, or something?

    • Ringed Herring Gulls from the colony of Texel in the north of the Netherlands have been observed foraging on the breakwaters off sandy beaches nearby, also outside of the breeding season. It turns out that specific breakwaters are visited by specific individuals, possibly driven by group hierarchy as well.
      I regularly see single dominant individuals in city parks especially in groups of Black-headed Gulls during the winter but I have a feeling these (and individuals such as H.501) are simply accepted and ignored whenever possible.
      Less dominant individuals definitely follow dominant ones who more quicker dare to approach food sources such as people feeding in city parks. In the groups that I observe there, a definite group hierarchy can be seen with dominant birds standing front row and the more timid birds (sub-adults, females, shy characters) standing at the back.

  2. Sometimes when I’ve fed the gulls myself, there will be one bird that approaches immediately and fearlessly – and all the other ones stand back and allow it to feed undisturbed (and if there are already gulls feeding, they will stop and move away, or be chased away very easily) until it’s had enough. But after that, the rest will run forwards, crowd together and squabble over the remaining food. They definitely do seem to know and remember which birds are the ‘alphas’ in the flock. It would be interesting to know if the ‘alpha’ birds also dictate to the flock as to where they will be travelling to feed…

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