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Friday, January 12, 2007

Breeding ecology of the Little Tern 6: Addendum

Breeding ecology of the Little Tern 6: Addendum

The breeding ecology of the Little Tern (Sterna albifrons) was posted as a five part series earlier - 1, 2, 3, 4 and 5.

Jonathan Cheah and Ashley Ng were both involved in documenting the series during the entire nesting period of about five weeks. Two photographers were necessary in order to minimise disturbance to the nesting grounds.

The birds feed as a flock, leaving the nests unguarded during this period. It was then that each nest was marked with plastic pickets as otherwise it would be difficult to relocate them. Also, this would prevent accidental trampling of the nests. Even after hatching, there was the constant danger of stepping on the chicks as they remained camouflaged, lying low and still. As far as were possible, defined paths were used, especially when moving down the valleys, to further minimise accidents. A total of about 60 eggs were counted from the various nests, of which about 75% of the chicks that hatched survived. Those that did not survive died within a few hours of hatching. A number of chicks were victims of feral dogs that roamed the area. Some eggs remained unhatched, mostly from clutches of more than two.

Documenting the birds was not easy as the parent birds were constantly dive-bombing the intruders. There was also the loud screeching of the birds as well as the echoes of the cries from above bouncing off from the sand to contend with.

All these distractions were enough to confuse predator and allowed the chicks to get into the shadows or among the vegetation. But obviously not the photographers, who persisted in order to being back the images.

Input and images by Dr Jonathan Cheah Weng Kwong.



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