Thursday, July 10, 2008

The Double-banded Plover at Ralph's Bay

I drive past the Lauderdale end of Ralph's Bay on many occasions, it's only a 10 minute drive from my abode. As I pass I often look, make that, always look, out across the bay, scanning for waders. At this time of year, apart from the flocks of Pied Oystercatchers, I can often see other small waders, scattered across the bay, feeding. But, to be honest, I rarely stop to identify what's there. A few days ago, while returning from an outing to the South Arm area that had only been mildly interesting, I spotted a few small flocks roosting close to the road and decided it was time to have a closer look.
During the Winter months, most of what to us are Summer migrants, are off to such areas as Mongolia and Arctic Russia, to breed. The likes of Eastern Curlew, Bar-tailed Godwit, Curlew Sandpipers and Red-necked Stint, that frequent this bay during our warmer months. But even during our Winter, we always have one migrant here, the Double-banded Plover. I always feel there's something rather odd about the Double-banded. For one, while there is an obvious advantage for migrant birds to seek warmer climes, such as more food and a better climate, the Double-banded migrates sideways! These plovers breed in New Zealand, usually away from the coast, and migrate to South-eastern Australia during our Winter. At least a fair number of them do ( some few thousand), the remainder staying in New Zealand, and Tasmania gets a large part of those migrating. Most stay on the coast, but some find their way inland, even into our high country. But if they can find enough food to survive our
Winters, and put on weight for the return journey, what is it that makes Tasmania unsuitable for breeding?
The flock at Lauderdale consisted of about 35 individuals, roosting in the pebbled area, only a few metres from the highway. With them were 20 or more Red-capped Plover and a few overwintering Red-necked Stint, all spreading out on the falling tide, as they began to feed. My main interest in the Double-banded was to get some useable shots of birds in their breeding strip, showing the two bands, and I reasoned that as they should be leaving our shores in August, they should be nearing full breeding plumage. So I was a little disappointed to find that only a few of them were anywhere near that stage. Plumages ranged from that of near breeding plumage of the bird at top left, to that of the individual at right, that still has a long way to go. The lower shot shows a part of the Red-capped Plover flock (and a solitary Double-banded Plover), which appeared to have a preponderance of males. In contrast to their slightly larger New Zealand cousins, they were all resplendent in their breeding plumage. Probably not surprisingly, as they are usually early breeders and I have found nests as early as late July, only a few weeks away.
Ominously, a floating drilling platform was operating not far away, as this area is under threat of being developed into a canal type housing estate, and this area is a 'conservation area'!


mick said...

Those are great photos of the Double-banded Plover - especially the photo of the mixed flock flying off. Up here in SE Qld we still see them into September before they fly off to NZ. I commonly see them in the Inskip Point area. I must go out there soon and see if I can see any changing into their breeding plumage.

BirdingTas said...

Hi Mick,
Thanks for your comments. If they all went to Queensland for the Winter, I think I could understand! The majority seem to visit Tasmania and Victoria, not, I suggest, very different from the climate in New Zealand. There is an old record of them breeding in Tasmania, but I think that has been largely discounted.

John Tongue said...

Hi Alan,
Lovely shots, especially of the flock in flight. I have never come across any attempted explanation as tho why the Double-bandeds have this strange migration pattern. Do you know of ny suggestions?

BirdingTas said...

Hi John,
Thanks for commenting. I've never really looked into this issue. A simple explanation may be that at some time in the past, the DBPs joined other migrants, such as the Red Knot and Bar-tailed Godwit. I believe that both those species regularly cross the Tasman Sea as part of their migration to and from the northern hemisphere. That might account for why only part of the population of DBPs migrate to Australia. A number of waders have colonised NZ from Australia, so is it possible that the DBPs originated from here !!

John Tongue said...

Thanks Alan,
A number of possible explanations for what is a most 'weird' occurrence!

Mosura said...

Great photos. I'll hopefully be down that way soon armed with a shiny new telephoto lens.