Tuesday, March 21, 2006

Measure of Success

A measure of a successful breeding season is probably most easily seen in the number of young birds produced. The accompanying images are of some of this years young Pacific Gulls, Kelp Gulls and Crested Terns seen recently on Marion Bay Spit. The gulls are most likely the progeny of birds nesting on Visscher Island, some few kilometres off shore. I'm not sure where the Crested Terns nest, but they too would have bred on offshore islands. Many of the young terns are largely still with their parents and although they are quite capable of fishing for themselves, they also seem quite able to "cadge" fish off passing adults. In contrast, the gulls are now left to their own devices and gather in species specific groups.
I must say that the continued increase in the number of Kelp Gulls causes me some concern and needs investigation, as I believe they constitute a threat to some of the areas in Southern Tasmania set aside as reserves for waders, both indigenous and migratory. They are breeding in sensitive areas such as Orielton Lagoon and the South Arm Neck, and their presence in coastal areas has an inhibiting affect on the use of those areas by waders. In the case of Orielton Lagoon, the gulls have occupied something like 40% of the land area at the
Northern end, and this is a no-go area for

No comments: