Tuesday, 25 October 2011

Extinction of Most Northerly Population of Eastern Bristlebird


The most northerly population of the endangered Eastern Bristlebird appears almost certain to be extinct.
This week, I spent some time in the Conondale Range, in the Sunshine Coast hinterland, surveying a site which had in the past been reliable for Eastern Bristlebird, with several pairs resident in the vicinity. Not a squeak. What I did see was a large feral cat, at precisely the spot where I last saw bristlebirds in the area in the early-1990s.
That particular spot is pictured here. I and others have tried unsuccessfully at this and other sites in the Conondale Range since the last bird was heard there in 2009. It appears almost certain that the population is extinct.
The Eastern Bristlebird was discovered in the Conondales in the early-1980s by Chris Corben. The population is distant from other populations in the Main Range and around the Queensland-NSW border, which are also threatened.
Several factors could be responsible for the bird’s demise. Feral animals clearly are a threat. One bristlebird released in the Main Range under Queensland’s captive breeding program was quickly taken by a fox.
Habitat may have been altered in ways which do not favour bristlebirds. In protected reserves in the Conondales and elsewhere, fires may be less frequent than in the past. Consequently, vegetation may have become too dense for the birds.

At the site this week, there was no evidence of burning in recent times and the open grassy woodland favoured by bristlebirds was choked by various weeds in parts. However, there were a few nice patches, such as the one pictured above, of the native grasses favoured by the birds. Fires in the past had not directly threatened the bristlebirds as they sought refuge in adjacent rainforest areas.

The prolonged drought through the 1990s and 2000s may have been the nail in the coffin. Following good rains over the past 18 months or so, conditions are looking ideal now; there was plenty of bird activity this week.

Whatever the cause, the Eastern Bristlebird appears almost certainly to be no longer present in this part of Australia.

5 comments:

  1. Hi Greg
    Birds Australia Southern Queensland during September 2011 conducted a week long survey with the Department of Environment and Resource Management in the Conondale Ranges at several sites including new secluded sites and Eastern Bristlebird was discovered at two sites. So the most northerly population of Eastern Bristlebird is not gone from this part of the world yet.
    However, if management of habitat suitable to the birds is not managed in the short term, reducing cattle, pig and deer impact, your conclusion may be true in the near future.

    Dez Wells
    Convenor
    Birds Australia Southern Queensland

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  2. That's exciting news Dez. Extremely happy to be proved wrong. Would love any more detail you may be able to provide.

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  3. Hi Greg
    I believe you are going up with Sheena Gilman and DERM to look for the birds in a couple of weeks good luck.

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  4. Thanks Dez, should be interesting.

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  5. Now I know more about these reports I am better able to comment. One bird was reported from the traditional South Booloumba track sites. Three birds were reported from Spikes track, which is distant from the traditional sites but in an area surveyed in the past without success.
    I was part of the group that this week attempted to corroborate the reports.
    I did not think the habitat at Spikes looked suitable for bristlebirds and it would be highly unusual if they were there. We did not encounter any indication of the birds being present. Others in the group attempted to corroborate the South Booloumba track report without success.
    With a critically endangered (possibly extinct) bird population such as the Conondale Range bristlebirds, it is essential that all reports be corroborated, so I think it best that the September reports be regarded as tentative.

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