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Saturday, 19 December 2015 04:47

Ever-changing Birds of Northern Sydney

Ross Rapmund gave a fascinating talk on the changing birds in northern Sydney. He started with a slide which compared the ten most common birds before 1900 with recent data. A hundred years ago the most common species were small birds with an average weight of 18 g (e.g. Superb Fairy Wren, New Holland Honeyeater, Golden Whistler and Willie Wagtail). Now the most common birds are much bigger with an average weight of 180 g (e.g. Common Myna, Noisy Miner, Magpie, Currawong and Rainbow Lorikeet).

The type of birds has also changed from predominately insectivores to honeyeaters and exotics that are mostly omnivores or nectivores. These changes have been brought about by factors such as:

  • habitat fragmentation through removal of tree canopy for urban development and 10/50 tree removal
  • decline in trees as they age with lack of replacement, particularly street trees deemed to be dangerous
  • weakened tree preservation policies
  • lack of political will to support new reserves and provide funding for the conservation of nature
  • inappropriate fire regimes with too much fire (hazard reduction) or too little fire (over-mature bushland losing biodiversity)
  • weed competition
  • pest and disease
  • chemicals such as outside insect bombs

Small birds play an important role in controlling insect pests that affect the health of trees. Bushland with a strong tree canopy in turn supports small birds. The continuing decline in bushland from development, exacerbated by climate change, creates a viscous circle of decline.

Ross provided many insights into bird characteristics and behaviour from his wealth of information of birdlife.

First launched in 2003, Eremaea Birds rapidly became the site of choice for recording bird sightings in Australia. In 2014, Eremaea Birds merged with eBird, allowing members to be part of a larger global birding community. Contribute to science and conservation by recording your own data and observations on http://ebird.org/content/australia.

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