Virginia got a remarakable picture yesterday of a Carrion Crow attacking a Cormorant which had perched in an unwisely exposed place in a tree near the Italian Garden. The Cormorant wouldn't be budged, and after a while the crow gave up and flew off.

Also by Virginia, the first record of a new species on the Serpentine, the Rubber Duck, Anas elastica. Moving rapidly in the wind, it frightened the other birds and they gave it a wide berth.

Doug Falder sent a fine shot of a Sparrowhawk with a Starling in Kensington Gardens.

Years ago I was walking to work across the Parade Ground and I also saw a Sparrowhawk with a Starling. It was so intent on keeping its prey that it stood its ground when I approached, and I got within three feet of it. Sadly, I wasn't carrying a camera.

Another fascinating video shot by Neil in Kensington Gardens, this time in slow motion, of Great Tits and Blue Tits coming to feed from his hand. This is probably close to the speedy birds' own perception of life. The eerie hoarse cries in the background, which sound like something from Jurassic Park, are the slowed-down shrieks of parakeets.

For some days there has been an American Horned Lark, Eremophila alpestris, at Staines Reservoir. David Element paid a visit and sent an excellent photograph.

Fran took this striking shot of Kestrels mating in Richmond Park.

Two pictures from Extremadura by Tinúviel. A Greenfinch perches on a railing. Greenfinches have become sadly scarce in the park here after they were hit by a respiratory disease, and I haven't seen or heard one in the past year.

A Spotless Starling, Sturnus unicolor, looks up apprehensively at a passing raptor. You can see from the droppings on the wall that it's outside its nest under a pantile.

This species, slightly larger than a Common Starling, has a small range around the western end of the Mediterranean.

A picture from Johanna van de Woestijne, who makes the excellent long videos on my YouTube channel. A young gull -- which I think is an American Herring Gull, Larus smithsonianus -- plays with a bit of bladder wrack.

On Wednesday I published a picture taken by David Holland in Cali, Colombia, of a bird he thought was a Great Kiskadee, Pitangu sulphuratus. I have now had an email from Duncan Campbell disagreeing with his identification, and identifying it pretty conclusively as a flycatcher. He sent me this picture from the web which is apparently of the same species.

But which species? This photograph appears on the web twice, once described as a Social Flycatcher, Myiozetetes similis, and once as a Rusty-Margined Flycatcher, Myiozetetes cayanensis. Duncan also sent me a photograph of the illustrations of both species from the enormous and authoritative Handbook of Birds of the World, volume 9, plate 40. I hope the copyright holders will forgive me if I reproduce these here for purposes of study. This is the Social Flycatcher, with the nominate species on the left and a subspecies on the right ...

... and this is the Rusty-Margined Flycatcher, similarly displayed.

Both have coloured patches on top of their heads, but according to HBBW these are often concealed (it doesn't say how) and are reduced or absent in juvenile birds.  The bird shown on Wednesday has stronger hints of 'rusty margins' on its folded primaries than the one in this blog post, but not enough to be conclusive.

Lastly, for those who are into identification of Colombian birds, here's another picture by David Holland. He can't identify this hummingbird because his reference book got ruined on the trip. I've tried on the web, but there is such a bewildering profusion of birds in Colombia that I couldn't find it.