Hello Chris and all,
The Spinifexbird entry on my website is worth a read (and a listen). I wish I had the time, and the wherewithall to present all the other species so fully
Cheers
Graeme Chapman ===============================
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Dear All,
It’s really worth looking at Graeme’s website http://www.graemechapman.com.au to see more great photos of the Spinifexbird, listen to the audios and to learn a little bit of this species’ ecology.
On his website, Graeme states:
“Throughout the spinifex grasslands the places to look for Spinifexbirds are along creek lines and in sheltered places where extra moisture allows the grass hummocks to grow the thickest.”
The University of WA and RAOU conducted research on the Spinifexbird on Barrow Island from 1990-93. We found that the Spinifexbird needs access to free water for drinking. This probably explains why Spinifexbirds are most often found near creek lines and in other moist microhabitats. The main source of that water on Barrow Island is dew that condenses on the spinifex clumps overnight or early morning. Spinifexbirds collected dew in their breast and belly feathers by rubbing themselves against moist spinifex grasses. The field water turnover that we measured in these birds indicated that they must be drinking the droplets of water that were collected by their feathers, rather than just relying on dietary water intake and metabolic water production.
The title and abstract of the scientific paper we published are shown below:
Ambrose, SJ, SD Bradshaw, PC Withers & DP Murphy (1996). Water and energy balance of captive and free-ranging Spinifexbirds (Eremiornis carteri) North (Aves: Sylviidae) on Barrow Island, Western Australia. Australian J. Zoology 44: 107-117 http://www.publish.csiro.au/paper/ZO9960107.htm
Abstract
The mean annual rainfall of Barrow Island, located about 90 km north of Onslow off the arid Western Australian coast, is 324 mm, 74% of which falls as cyclonic rain between February and May. Spinifexbirds captured in May 1992 had a mean body mass of 12.3 +/- 0.3 g and a total body water content (TBW) of 774 +/- 1.6%. In December 1992 the mean body mass was significantly lower (11.7 +/- 0.2 g; P < 0.05), despite a TBW of 73.4 +/- 1.0%. Spinifexbirds maintained water balance in both seasons, but water flux rates were significantly higher in May (P = 0.01). Respective influx and efflux rates in May were 0.70 +/- 0.30 and 0.72 +/- 0.03 mL (g day)(-1) compared with 0.60 +/- 0.04 and 0.57 +/- 0.04 mL (g day)(-1) in December. Field metabolic rates (FMRs), measured with doubly-labelled water ((3)HH(18)0), did not differ significantly between the two periods. The mean FMR in May was 6.8 +/- 0.6 mL CO2 (g h)(-1) compared with 7.2 +/- 0.9 mL CO2 (g h)(-1) in December, similar to rates predicted by Nagy and Peterson (1988) for a similar-sized passerine. The thermoneutral zone (TNZ) of spinifexbirds, determined by metabolic laboratory trials in December, extended from 30 to 39 degrees C. The standard metabolic rate (SMR) within the TNZ was 2.9 +/- 0.1 mL O-2 (g h)(-1), which is up to 20% lower than predicted values. Body temperature was maintained at 39.1 degrees C in the TNZ, but birds became hyperthermic at ambient temperatures (T(a)s) higher than 35 degrees C, with body temperatures reaching 44 degrees C. Wet thermal conductance and evaporative water loss increased markedly at T(a)s > 35 degrees C. The data suggest that spinifexbirds have limited physiological adaptations to desert conditions compared with some other arid-zone birds.
Stephen Ambrose Ryde NSW