I can remember observing flocks of Red-breasted Mergansers off of Lake
County in November in the early eighties. They were swimming and diving
from west to east in flocks that numbered a few thousand each. Certainly
many tens of thousands in total. Their feeding behavior was very
interesting. As each flock moved along the birds at the rear were constantly
taking flight and landing at the front of the flock- a strategy that allows
all individuals an equal opportunity at the bounty.
Their primary prey species all fluctuate in numbers from year to year- shad,
smelt, and alewives, and they are found at different distances from shore
depending on conditions. I also wonder if they are utilizing gobies as a
food source. They are abundant now in Erie. What a mess invasives have made
of Lake Erie's ecosystem.
Dave Hochadel
----- Original Message -----
From: "John Pogacnik" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, November 30, 2009 9:21 AM
Subject: [Ohio-birds] Red-breasted Merganser numbers
I have a heard a lot of people discussing the decline in red-breasted
merganser numbers over the years. One of the most amazing sights I have
ever had a chance to witness was watching approximately 250,000 red-breasted
mergansers pass by the Vermilion area. The following year ODOW surveys
confirmed close to that number. It was stated that the majority of the
red-breasted merganser population was using Lake Erie as a staging area.
What happened?
Those sightings were during the 1980's. Since that time it seems that there
has been a steady decline in red-breasted merganser numbers on Lake Erie.
In the early 1990's I remember seeing flocks that probably exceeded 100,000
birds. November was the best time to see this and the Huron-Vermilion area
was the best location. Last weekend I was at Huron and didn't see a single
red-breasted merganser. There are decent flocks around especially east of
Cleveland, but most of these flocks are 5,000 or less. Where are the bigger
flocks?
Should we be concerned with this decline. Are the red-breasted merganser
flocks spreading out over the Great Lakes, are they passing us by, or is
there a major decline? As far as waterfowl surveys go, they seem to lump
all of the mergansers since thay are not as important to hunters. Vic Fazio
had numbers of Ohio red-breasted mergansers through the years. Hopefully he
is out there and can post them. There appears to be something going on
here. Were the 1980's unusual that for some reason there was a massive
increase in mergansers. Maybe there is something to this. If you go to the
Christmas Bird Count website and create a graph for red-breasted merganser,
from 1960- present for the United States, there is a large spike in numbers
from about 1982-1993 Before and after the spike, the graph is pretty level.
Interestingly, if you create a graph back to the 1930's, there was a shorter
spike from approximately 1937-1942. Maybe the question should be, what
caused the spike in numbers in the 1940's and 1980's. Also how do the last
few years numbers locally compare with numbers in the past outside of the
peeks. The Christmas Bird Count data is limited in use for Ohio since most
of the mergansers have departed by the time of the counts. Although data
shows there has been an increase over the last few years in Ohio.
If you want to play with the Christmas count graphs, here is the link.
http://audubon2.org/cbchist/graph.html
John Pogacnik
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