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Posts tagged “Galliformes

Spruce Grouse Foraging

While Ruffed Grouse are plentiful throughout most of New England, one has to go to northern Vermont, New Hampshire or Maine to see its cousin, the Spruce Grouse.  Associated with boreal forests, this largely herbivorous bird feeds primarily on the needles of pine, spruce and fir (a small amount of animal matter is consumed in the summer as well as ground vegetation). Especially in the winter, a large volume of conifer browse is consumed in order to meet energy demands.

The grouse holds the needle between the tips of its mandibles and breaks it off by flicking its head.  This action, and the fact that Spruce Grouse feed exclusively on needles in the winter, leads to the wearing off of the tip of the bird’s upper mandible by spring.

If you are searching for a Spruce Grouse, you might want to concentrate in the middle of the crowns of trees, as this is where the birds tend to forage. Theories for this preference include the fact that needles in this location have higher nutritive value, branches provide sturdy support, and grouse can see approaching avian predators while remaining partially concealed. (Birds of North America, Cornell Lab of Ornithology). (Photo: male Spruce Grouse browsing on Tamarack needles and (inset) looking for grit on the ground.)

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Ruffed Grouse Winter Adaptations

12-8-12 ruffed grouse foot IMG_3524The Ruffed Grouse has both behavioral and physical strategies for dealing with the cold, snow and ice of New England winters.  Three of the physical changes that take place in the fall are evident by looking closely at a grouse’s legs, feet and beak. The feathers on its legs grow thicker and further down towards its feet, to provide better insulation.  Small comb-like growths of skin, called pectinations, develop along either side of each toe.  These increase the surface area of a grouse’s foot, and serve as snowshoes in deep snow.  They also help the grouse cling to icy branches while it quickly snips off poplar and other buds at either end of the day.  And on its beak, feathers expand downward to cover its nostrils, slowing the cold air and giving it a chance to warm up before it is inhaled by the grouse.


Ruffed Grouse Crop Contents

Some birds, especially those that eat seeds, buds, leaves and nuts, such as ruffed grouse, eat food very rapidly, faster than it can be passed through the digestive system.  These birds usually have a pouch-like crop where food is stored to be digested later, when the birds are not out in the open, susceptible to predators.  (see 10-24-12 Naturally Curious post)  This rapid consumption and storage of food by grouse, often at dawn and dusk, is referred to as “budding.”  Examining the contents of road-killed grouse crops is one way of learning more about this adaptive behavior.  Assuming some of my readers might (?) share my curiosity about the diet of grouse, I occasionally post the contents of a grouse crop I’ve recently examined.   My most recent dissection revealed that the grouse had switched from its herbaceous summer diet to its more woody winter diet — its crop contained no less than 232 male birch flower buds, or catkins.  (Disclaimer:  This crop was not that of the grouse that was the subject of the 11-9-12 post.)


Ruffed Grouse & Engines

Ruffed grouse, also known locally as partridge, are so well camouflaged that sometimes the only glimpse you get of them is when they explode right in front of you in an attempt to fly away from you. Occasionally, however, one will allow you more than a cursory look (and an opportunity to photograph it up close). This often happens when someone is running an engine, be it lawn mower, wood splitter or 4-wheeler. Upon hearing the sound, a grouse may walk rapidly towards it and linger in the vicinity for hours. Perhaps the occasional female grouse mistakes the sound of an engine for the alluring drumming of a male grouse, as the drumming sounds uncannily like a lawn mower starting up!


Hen Turkey with Two Broods

If you look closely, you’ll see that there are two broods accompanying one hen turkey in the photograph — seven smaller, younger poults (nearest the bottom of the photo) and ten larger poults (closer to the top of the photo). Chances are that the hen is not the mother of all the poults. It’s likely that the young of another hen joined a hen and her brood. While this is not common, it is not unusual to see two or more hens with their respective broods flock together during the summer. First year males leave the hens and female poults to form independent flocks in the fall. Females (several hens and their poults) often join together during the winter months forming large flocks, and in the spring, as the breeding season approaches, break up into smaller flocks which will include one or more males.


Ruffed Grouse Eggs Hatching

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If you stumble, as I did, upon a female Ruffed Grouse whose eggs have recently hatched, be prepared for her fury! When I entered nearby woods, the mother charged at me with her crest raised, tail spread and ruffs (black neck feathers) erect. (Her chicks had dispersed prior to this, well hidden by their camouflaged down.) Fiercely protective, female grouse with young are known for their aggressive behavior. A large grouse might weigh two pounds – to tackle a human weighing more than 50 times as much as oneself is pretty impressive.


Mystery Photo Solved!

Well done, those of you who guessed Wild Turkey, which was most of you! Charlotte Carlson not only discovered their nest, but managed to photograph the hen and tom turkey in the act of making the eggs!