Monday, March 24, 2008

Long Haul to Fledging.......Pied Oystercatcher

I've watched the progress of two Pied Oystercatcher chicks over the past few months as they've grown. They are the progeny of a pair of POs that nest close by the oyster sheds at Pipeclay Lagoon. Their first attempt was most probably washed out, as they nested on a shingle bank close to the high tide line. This is a familiar fate for many oystercatcher nests, and with global warming bearing down on us, this is a potentially serious threat. I never found these chicks at the newly hatched stage, and I'm guessing that the age of the two at top right, is about a couple of weeks. The shot taken around the third week of January. As you can see, they're both in the water, and the high tide strategy against predators, is to swim away. PO young are accomplished divers too, and will dive, as a last resort, when hotly pursued.
The shot of the 2 youngsters running, was taken on the 8th February, and by now there is a marked difference in their size. Less than 2 weeks later, towards the end of February, one runner had disappeared, and I can only speculate on the cause. Given the size difference, perhaps it was food related, but predation from a range of likely suspects, ranging from harriers to gulls is possible, as is the possibility they were taken by cats or dogs. The latter a real possibility, as I've seen dogs being exercised off lead, along this very narrow stretch of beach.
By the end of the first week of March, when the shot of the remaining chick with one of its parents was taken, the chick is approaching fledging, but still dependent on its parents for food. This juvenile was soliciting the adult for food, constantly walking round and round its parent. Occasionally it would flex its wings, and the primaries were clearly not fully developed for flight. By the 18th of March, success, it could finally fly! Rather hesitantly, and somewhat reluctantly, but it could fly. So after around 8 weeks it had made it, but its still dependent on a parent to feed it.
I'll continue to keep an eye on its progress.


Murray Lord said...

I trust you are looking out for South Island Pied Oystercatchers in your travels? If they can turn up in NSW they can turn up in Tasmania. By the way, these birds are now officially "Australian Pied Oystercatchers"...

BirdingTas said...

Hi Murray,
Not really looking for the SIPO, but live in hope!! As far as the new names go--a pox on them. It's taken me years to stop calling the Masked Lapwing a Spurwing, and I still have problems with others. Until I get a field guide with the new names in, I'm afraid I'm stuck with the "old" ones!

mick said...

Great photos! And very interesting to see a series like that. I have not yet seen young Pied Oystercatchers although there are a number of apparently resident pairs around the Bay here - Tin Can Bay inlet in SE Queenlsand

BirdingTas said...

Hi Mick,
I think the shots owe much to the oystercatchers nesting so close to the oyster sheds and becoming used to human activity. It also made it easy to be sure that I was photographing the same birds!