Thursday, November 15, 2007

a grouse equation

I prepared Momo's first grouse this morning, saving the wings for training and the tail-fan to commemorate His Senior Majesty's achievement, and of course the breast meat (which I will most likely eat at Thanksgiving). I will do my best to sex the bird once I get home this evening and can take a little time to examine the tail-fan.

Ruffed grouse being opportunistic feeders, they adapt what they eat as seasons, cover, and appetite change. While many authors point to the frequent overlap between alder trees (which provide moisture- and nutrient-rich buds) and grouse populations, their research over time and place invariably notes the diversity of grouse food. Being a curious type, I was interested to examine the crop contents of the bird we had taken. The crop is the sac-like container in the espohagus prior to the digestive tract -- and at least for the Spruce Grouse can hold up to 10% of the bird's body weight for digestion at night (while predators are also asleep). Grouse, like many other gallinaceous birds, will also consume a significant amount of gravel to help in breaking down and digesting plant cellulose. We didn't find any in the crop of this bird -- but did find clover and small fern leaves that, perhaps not surprisingly because they hadn't entered the digestive tract, still smelled wonderfully fresh (despite being frozen and defrosted).

(Here's a nice outline from Pictured Rocks National Lakeshore for a Wildlife Management Activity Guide for teachers to use in their biology classes and then share their data with the NPS. And here's a nice reference article from 1928 of what grouse were eating up around Syracuse, NY.)

My friend, Dudley, has a nice simple equation for finding grouse: gravel, water, greenery, and cedar = grouse. The greenery largely offer food, while the cedar could most likely be subsituted for other evergreens because it provides good roosting cover above ground predators and visual coverage from raptors flying above.

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