Monday, September 22, 2008

19th September 2008: Tanjung Tokong, Penang, Part 2: Plovers

As usual, Lesser Sand Plovers were the commonest wader on the mudflats, and, as usual, they were aggressively defending feeding territories. Once again, the adults seemed to dominate the juveniles.

Here's a 1st winter plumaged bird, nicely illustrating the fact that juveniles undergo a body but not a wing moult. Hence the body feathers are plain and adult-like, while the wing and tail feathers show the broad pale fringes distinctive of juveniles.

This adult is interesting; the bill looks significantly shorter and differently shaped from the 1st winter, which shows the long bill typical of the 'schaeferi' race. Could this be 'atrifrons'?

I had a good chance to observe a couple of feeding Greater Sand Plovers. This is an adult...

...while this is a 1st winter. The pale fringes on the wings have largely worn away on this bird.

These two were much more tolerant of each other than Lesser Sand Plovers would be.

Nevertheless, there was some tension, as could be seen by the two birds exchanging insults!

I was intrigued to see that both birds had serrated cutting edges to their upper mandibles - presumably to help them keep a hold of wriggling crabs.

Eventually the altercation became physical, and surprisingly, the young bird chased off the adult, which retreated to a safe distance.

So the young bird won this particular 'turf war'.

A couple of shots showing Greater and Lesser Sand Plovers in flight. I've read that the longer toe projection beyond the tail is a useful id feature of Greater, but in the field I've never found it to be of any practical use. The head and bill structure are still the clearest ways to separate the two for me. In the top picture, the Greater Sand is on the right, and in the lower one there is a lone Lesser bottom left.

Welcome back! Away on the tideline I noticed a single "White-faced" Plover. It has arrived almost a month earlier than my previous earliest record. Just as in October 2006, when I first noticed the odd pale birds, the "White-faced" has turned up with a 'normal' Kentish Plover. A Greater Sand Plover provides a size comparison.

The white-fringed coverts, short lateral breast patches, white lores and lower ear coverts and pale legs are what set these birds apart from typical Kentish Plovers.

The faint band across the forecrown, and gingery rear crown and ear coverts, together with the mostly white lores, make me think this bird is probably an adult male in fresh non-breeding plumage. Hopefully more will arrive over the coming weeks.

1 comment:

Tyto Tony said...

Nicely observed! The bill serration is a revelation.