Again this morning (December 10) in several minutes of watching I saw a few Mallards, at least 2 males and a female, in the vicinity of a Common Goldeneye flock on the reservoir upstream from Wilder Dam on the Connecticut River. The number of goldeneyes in the flock on the water varied over time as small numbers of goldeneyes flew in or out, but at one point there were as many as 13 goldeneyes together on the water. A few Mallards were seen swimming toward the area of the goldeneye flock and at other times swimming within the area of the goldeneye flock.

Again today, my impression was that a few Mallards were deliberately choosing to associate with the goldeneye flock rather than go elsewhere on the large reservoir. If this impression is correct, then a question is why should some Mallards seek out the company of goldeneyes?

One conceivable explanation might be that the diving by goldeneyes somehow brings food to the surface. Although individual Mallards in the vicinity of goldeneye flocks sometimes bend their heads forward towards the water, actual feeding by those Mallards has not been seen and would be difficult to detect partly because of the long distances of observation. My thanks to Ted Levin who has kindly reported from his observations that Common Goldeneyes extensively feed on animal foods, and this agrees with other sources, both in print and online. Although goldeneyes also sometimes eat aquatic plants, my earlier presumption of plant foods seems unlikely. The evidence is so far poor for the idea that Mallards approach goldeneye flocks to obtain food.

As noted before, another explanation might be that Mallards gain an advantage in avoiding predators by joining a goldeneye flock, but evidence for this seems also poor.

Could it be that Mallards are attracted by the activity of the goldeneyes? The goldeneyes move around a lot, whether diving, reemerging from the water, swimming along the surface, flying in or out, or occasionally displaying. Perhaps the Mallards are simply being curious?

George Clark
Norwich, VT




 


To post messages, send e-mail to:  [log in to unmask]
Set your e-mail application to PLAIN TEXT ONLY to post messages.
To contact the list owner:  [log in to unmask]
To unsubscribe:  E-mail this command to [log in to unmask]  UNSUBSCRIBE UV-Birders
To change your e-mail address:  E-mail this command from your old address to: [log in to unmask]  CHANGE UV-Birders [new e-mail address]

Web based archives and subscription management are available at:
http://listserv.dartmouth.edu/Archives/uv-birders.html