[CT Birds] Not Ring-necked but Common mergangers-sex ratio.

Boletebill boletebill at yahoo.com
Fri Mar 9 09:52:21 EST 2012

Just by way of adding to the duck sex ratio discussion I'll make a brief comment about the winter population of Common Mergangers on the lower Ct River.
Male Common mergs far outnumber females on the lower Ct River in Winter.  Also the males tend to associate with other males through-out the early months of winter (Dec.-Feb) even though females are present on the river. The females, present in small numbers, either stick together apart from the males or 1 or 2 may be present in a group of 6-12 males. beginning  in late Feb. males seem to begin departing the river and males and females begin to start pairing up. Now, the first full week of March, there are still small groups of Common mergs on the river but many are paired or in small groups of mixed males and females while there are still a few groups that are exclusively males.
I'd have to say that my general observation of the population trend for Common Mergs on the lower Ct River is that each of the past 3 or 4 years have tended toward a declining winter population. The same trend here holds for Great Cormorants (declining pop.) and WINTERING Bald Eagles. Even accounting for the mild ice-free winter this year it's clear that the large winter population of Bald Eagles on the lower Ct river is declining. From the huge number of eagles we saw in the late '90's and earl y to mid- 2000's (40, 50, even 60 eagles) we are now seeing between 10 and 20 eagles during winter bird tours.
There seems to be a belief in place that many south bound wintering eagles are continuing further south now(i.e. not staying in southern CT on the CT river) and are part of the growing populations on the Hudson River and Delaware and Chesapeake bays. I don't have any hard data to back this belief up and I only offer the thought that this MAY be what is happening as anecdote.
Bill Yule
"For those who hunger after the earthly excrescences called mushrooms."

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