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- Feb 28, 2007
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Last night I slept out on one of the unihabited islands in Western Lake Erie - Middle Sister Island. Actually, this Island constitutes the most Southern point of Canada.
The goal was to collect female mayflies from this site to collect their eggs. However, it was one of the nights when all we collected was males. Oh well, I can still use the males in another experiment. We need to catch the critters here because this particular Island sits in the path of the Detroit River plume and has rather high contamination as a result.
Here is a shot of a mayfly. This one is a female, one of about 6 we collected, but we really needed about 600. There are two species of mayflies in habiting Lake Erie - Hexagenia limbata and Hexagenia rigida. The one pictured below is H. rigida. You can tell by the wings, in this species they are fully clear. For H. limbata there is a pigmented section on the wing that looks alot like a Nike symbol.
The island has a large herring gull colony and is also being colonized by double crested cormorants. The cormorants are tree nesters and their guano is contributing to the death of the Island. Basically, over-fertilizing it and the native vegetation, primarily Carolinean forest, cannot take the heavy nitrogen burden and soil acidification from the inputs. The cormorant populations have been exploding (not literally - but some people wish that were the case) for the past 5 years or so. Much of the success of these animals has been attributed to their use of fishfarms in southern U.S. and they have changed their flyways as a result.
A great egret nestling followed by a great blue heron nestling
Some gulls
Here is an interesting find. This juvenile has a crossed bill, a classic sign of dixoins and PCBs which is one of the reason we came to sample this island. Crossed bills used to be very frequently observed in the 1970's but the number of incidences has dropped quite a bit. This was the only one I saw on the island.
The goal was to collect female mayflies from this site to collect their eggs. However, it was one of the nights when all we collected was males. Oh well, I can still use the males in another experiment. We need to catch the critters here because this particular Island sits in the path of the Detroit River plume and has rather high contamination as a result.
Here is a shot of a mayfly. This one is a female, one of about 6 we collected, but we really needed about 600. There are two species of mayflies in habiting Lake Erie - Hexagenia limbata and Hexagenia rigida. The one pictured below is H. rigida. You can tell by the wings, in this species they are fully clear. For H. limbata there is a pigmented section on the wing that looks alot like a Nike symbol.
The island has a large herring gull colony and is also being colonized by double crested cormorants. The cormorants are tree nesters and their guano is contributing to the death of the Island. Basically, over-fertilizing it and the native vegetation, primarily Carolinean forest, cannot take the heavy nitrogen burden and soil acidification from the inputs. The cormorant populations have been exploding (not literally - but some people wish that were the case) for the past 5 years or so. Much of the success of these animals has been attributed to their use of fishfarms in southern U.S. and they have changed their flyways as a result.
A great egret nestling followed by a great blue heron nestling
Some gulls
Here is an interesting find. This juvenile has a crossed bill, a classic sign of dixoins and PCBs which is one of the reason we came to sample this island. Crossed bills used to be very frequently observed in the 1970's but the number of incidences has dropped quite a bit. This was the only one I saw on the island.
