Sunday, November 27, 2011

Crake City - Thomson's Lake

“This must be Crake City”, my son proclaimed. Summer at Thomson’s Lake is probably as close as you can get to Crake City in Western Australia. We had started the morning at Kogolup Swamp but the water levels there were too high. It was ankle deep at the edge of the shallowest rushes and the crakes could be heard tucked up deep in the rushes where our spying eyes could not see them. We moved to Thomson’s Lake which dries earlier and had plenty of mud exposed at the edges of the rushes. Crake heaven. Well, crake watching birders' heaven!

Australian Spotted Crake at Thomson's Lake.

During the South West Waterbird Study from 1981 to 1985, Thomson’s Lake recorded the highest counts of Baillon’s Crake (Porzana pusilla) and Australian Spotted Crake (P. fluminea) from the 3131 surveys of 197 wetlands [1]. With a count of 19 Spotless Crake (P. tabuensis), Thomson’s Lake also recorded the third highest count during these surveys marginally behind the 25 recorded at Grasmere Lake (Lake Powell) and the 20 at Benger Swamp. The size of the highest counts for Baillon's and Australian Spotted Crakes at Thomson's Lake in these surveys, five and 20 respectively, is testament to the difficulty in surveying crakes numbers.

Their secretive nature means that they spend more time within thick rushes or sedges than on the edges of their often impenetrable neighborhoods. In December 2007 Alan Collins recorded 41 Baillon’s Crake, 32 Australian Spotted Crake and 23 Spotless Crake on a perfectly timed survey at Thomson’s Lake. These numbers of crakes were only recorded over a week when the water had receded so much that only one large clump of Typha still had water at its edges. By the end of the week the water had dried too far out from the rushes and the crakes had moved on. Crakes are amazingly mobile birds that will move quickly to a better wetland when conditions are past their best.

Spotless Crake are the most commonly encountered crake in southwest Western Australia and any wetland with a reasonably sized stand of rushes or sedges is likely to have Spotless Crake present. Nonetheless, it was still only recorded in 31 of the 197 wetlands during the 1981-1985 surveys [1], while Baillon’s Crake and Australian Spotted Crake were both recorded in 8 wetlands.

Spotless Crake foraging at Kogolup Lake. How do they stay so clean-looking in all that mud?

Spotless Crakes are handsome birds dressed in blue-grey velvet suits with a coppery brown jacket on their back. Their bright red eyes are often intently searching for small insects in the mud. The juveniles are much duller with paler grey suits and grey-brown jackets but they are just as enjoyable to watch scurrying around in search of a meal.

Young Spotless Crake lurking in the Typha.

Baillon’s Crake is the smallest of the three species and also the most globally widespread as it also occurs in Africa, Eurasia and Asia.

At the other end of the spectrum is the Australian Spotted Crake, which is the largest crake in Australia and is confined to Australian wetlands. The spots and streaks on its back are so busy that they remind me of some of those jumpers worn by Darryl Somers on Hey Hey It’s Saturday 30 years ago! However, Darryl was unfortunate not to have the lovely green legs and bill which combined with bright red eyes makes the Australian Spotted Crake a stunner!

Baillon's Crake at Thomson's Lake.

While we had only counted 4 Baillon’s Crake, 12 Spotless Crake and 14 Australian Spotted Crake at Thomson’s Lake that morning we were pleased to see adults of all three species and juveniles of Spotless and Spotted Crake present in a 30 meter long stretch of Typha. On that day there were still large areas of inundated rushes and sedges so the crakes were not yet concentrated into the very last patches of wet or damp rushes. A few weeks later and it really would have been Crake City!

Immature Australian Spotted Crake at Thomson's Lake.

[1] Jaensch RP, Vervest RM & Hewish MJ (1988) Waterbirds in the Nature Reserves of South-Western Australia 1981-1985: Reserve Accounts. RAOU Report No. 30. 

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