Black-headed gulls paddling

I've written about foot-paddling for worms on wet grass in Herring Gulls and Common Gulls in this blog before. My local park has flooded in the last few weeks and Black-headed Gulls have moved in, enjoying the flushes, which bring up a lot of worms. Black-headed Gulls foot-paddle in water, but apparently they don't do it on wet grass like other gulls (but see the clips by Ralph Hancock in the comments). In an article on foot paddling in gulls Niko Tinbergen speculated that the reason could be that Black-headed gulls are not heavy enough to produce the vibrations on the ground that stimulate the migration of worms to the surface.
I had never seen Black-headed Gulls paddling on water before. This morning there were at least 30 Black-headed gulls and I noticed a one briefly paddling on shallow water, and checking in front of its feet. A young gull came along and when at the same spot it started paddling too. I managed a short clip of it.

After a while one of the young ones got a worm, unclear if due to the paddling. Walking around the pools on areas where the gulls don't go by the road it was apparent that there were a lot of dead (drowned?) worms. I think that's what the gulls are after in the flood. The Herring gulls were also energetically pulling grass and leaves and soil from the shallow puddles to expose food.

More information
Tinbergen, N. Foot-paddling in gulls. Br. Birds 55, 117 (1962)

The Viking gulls

A flock of about 100 common gulls winters in the park, they arrive at the end of September/October and are around most of the time until the end of March. They are very excitable and their squeals provide the background noise of the park in winter, especially when visitors empty their bags of bread by the side of the pond. A cacophony of calls and chases ensues while the gulls pick the bounty fast, before the ducks and geese have the chance to react.
 Is not only bread though for the park gulls, there are very quiet times, especially during the middle of the week, and the gulls will move onto the grass, looking for worms and other invertebrates, watching the ground intently as they walk.

 In wet days they can be seen 'dancing' (foot-paddling) to entice the worm to the surface of the soil. Like so.

Then they spend some time just flying in circles over the park, in a flock, I am not sure if in preparation to roost, although I am not sure where they spend the night.

A quiet moment in the flock, with preening, snoozing and yawning by the pond.

This is an adult one on winter plumage. Note the yellow bill with faint dark ring near the tip and the yellow legs, and spotty head.

on the 3rd of February this adult looked very nice on the snow, still in winter plumage.

On the 20th of February this adult had an almost white head and a thin red eye ring.

A close up of an adult's head showing mainly yellow bill, red ring. Note the scruffy back of the head, showing the ongoing moult towards a completely white head plumage.

I find them endlessly fascinating and can't stop myself from photographing them, and they are often co-operative, as they are so used to people. When I noted that the flock disappeared each year, one day in March or April I wondered where they would go in the summer, to breed. I need wonder no longer, these gulls come from Bergen, in Norway.
While watching them one day in January I found a couple of Common Gulls with plastic colour rings. I spent some time looking at the legs of many gulls since that day, but I didn't spot any other ringed ones. I managed to get photos where I could read the code and submitted the samples to Euring. I got an e-mail the same day from Morten Helberg with details of their ringing and recoveries. Since then, I have seen the ringed gulls a few times, and managed to get their portraits.

This is J2EX, sex unknown ringed its first autumn (1st calendar year in 2013) which means now should be in its 3rd calendar year (almost adult), although the bill and legs are still grey/bluish and doesn't have a red eye ring or prominent wing 'mirrors'. This is its ringing/recovery history:

15.09 2013 Byparken, Bergen, Hordaland, Norway
17.09 2013 Tveitevannet, Bergen, Hordaland, Norway
20.09 2013 Tveitevannet, Bergen, Hordaland, Norway
21.09 2013 Byparken, Bergen, Hordaland, Norway
14.06 2014 Kilnsea, Humberside, Great Britain
14.01 2015 Pearson park Hull, Humberside, Great Britain (the photo above is from yesterday, also observed 22/01/2015)

This is JV47, Sex male age, 1 cy when ringed last October, so it's in his first winter. He still called like a gull chick when feeding, and adopted this hunched chick posture. Legs and bill base pinkish.

This is it's ringing/recovering history:
05.10 2014 Tveitevannet, Bergen, Hordaland, Norway
(in the month after it was ringed the flock came back to Pearson Park)
14.01 2015 Pearson park Hull, Humberside, Great Britain 

Looking at photos yesterday, I found another ringed common gull, from the 20th of February. It looks like a first winter bird. The code reads JR20. I will update the post when I hear back from Euring.

It is very nice to know where these gulls spend the summer, but something equally rewarding is to know them as individuals. The rings have allowed me to recognised them in my visits to the park. I will look forward to them coming back in years to come, as gulls can be long lived. A typical Common Gull lives for 10 years (the record is 27).

Dancing for worms

I had blogged before on this curious gull behaviour, although that occasion I didn't manage to see the effects of the gull 'worm dance' or foot-paddling. This morning, on the university ground, a Herring gull did the worm dance energetically, and very effectively on the wet grass. I watched as it captured four or five good size worms more or less in the same spot in a few minutes. Breakfast sorted!



UPDATE 6/08/17. I just found this interesting article by Niko Tinbergen in which he discusses the behaviour in gulls and other birds. He calls it 'foot paddling' and the behaviorr includes paddling in shallow water:
Tinbergen, N. (1962). Foot-paddling in gulls. British Birds, 55(3), 117-120. Here.

Dancing Gulls

I went for a long walk the other day and passed next to some grassy sport grounds. Several Herring Gulls and a Woodpigeon were on it. The Woodpigeon and some of the gulls were lazily dozing on the ground, enjoying the early morning sun. Two of the gulls were doing something more interesting. They were patting the ground moving their feet rapidly, as if running on the spot. After a little while, they stopped and looked into the grass intently, only to start their tap dance-and-watch sequence all over again. Their sustained interest indicated this behaviour was related to obtaining food. Occasionally they pecked the ground, but if they caught something it was small and I coudn't see it. In any case they did not seem to catch any good size earthworms. I took some photos and a very poor quality video. Yesterday I saw the same thing in the local park grass, but this time it was a Common Gull. I got a few answers in The Last Word, the Question and Answer section in the New Scientist. I also found some better quality than mine:

Here, the gull is seen actually catching a couple of worms. It is quite an intriguing behaviour reminiscent of the facts behind the World Worm Charming Championships, which take place in the village of Willaston (Cheshire, U.K.) since 1980. Participants must encourage worms to the surface of the ground by vibration means only (no digging allowed!). The current record is impressive: 567 worms in 30 min from a 3 sqm plot. I was also wondering if the gull behaviour arose when they feed in puddles in the beach and when adopting it on grass, found by chance it actually encourages worms to surface. I can only say, Blackbirds, learn!

Common Gull checking for the effect of its dance