Monday, January 21, 2008

It isn't Easy Being Female

It is for me!
No complaints from the gal side of BirdCouple.

But female Ring-Necked Ducks may disagree.


On a recent birding jaunt with Paul Baicich, our dear friend pointed out that the male Ring-Necked Ducks outnumbered the girls by at least 4 to 1.


We noticed the same disproportionate number of males vs females in Ring-Necks while birding this weekend in Prince George's County.


Photo: Dave Herr

So, my first thought, naturally, was ....

Wow, with that ratio I defiantly want to come back as a female Ring-Necked Duck!


Until Paul pointed out that there was probably a pretty good reason that there aren't as many gals in the flock.


One of the reasons could be brood parasitism. Brood parasitism is when one bird lays her eggs in another's nest and leaves the chick hatching duties to someone else.


Cowbirds dumping their eggs in warbler nests is probably the most well known of brood parasitism. But, it is also quite common in ducks.


While checking Wood Duck boxes at Huntley Meadows Park last year, we noticed some boxes literally crammed with eggs, most likely dumped by one or two females who are not into doing the nest sitting duty.


The more eggs to hatch, the more bills to feed, the more at risk the female is to predation.


Perhaps, but I found nothing that suggests Ring-Neckeds have a more common rate of hosting parasitic eggs than Mallards.


The nests of the Ring-necked Duck are built on floating islands or in open marshes, close to water. Maybe females are more at risk from general predation during nesting than Canvasback females who prefer to nest in marshes above shallow water or on dry land.


According to The Boreal Songbird Initiative , "Ring-necked Ducks are more generalized feeders than other diving ducks. They eat mostly plant matter like seeds and tubers of submerged vegetation, but also feed on snails, insects, leeches, and other aquatic invertebrates. The diet varies for females during high energy cost periods, such as egg production and nesting, when they will consume more protein rich invertebrates."


Is something in the protein rich invertebrates toxic to females?


Ring-necked Ducks also have one of the highest lead shot ingestion rates among North American waterfowl. Lead shot has been banned in North America for several years, but pre-ban lead pellets can still be found in many wetlands.

Perhaps, females are more at risk to lead poisoning because she, potionally, ingests more sucken lead pellets as she raises her young in the marsh.


Theories!


But for now, the male Ring-Necks hanging in our local birding lakes, look like they face something similar to human males living in Alaska .

2 comments:

Nervous Birds said...

I'm ringin' my neck trying to pick the best theory.

Interesting. Very interesting.

Larry said...

That's a very informative post-I knew about cowbirds but hadn't heard about the ducks-