View source for Grouse

{{other uses}}
{{Taxobox
| name = Grouse
| fossil_range = [[Early Pliocene]] to recent
| image = SageGrouse21.jpg
| image_width = 200px
| image_caption = Male [[sage grouse]]<br/>''Centrocercus urophasianus''
| regnum = [[Animal]]ia
| phylum = [[Chordata]]
| classis = [[Aves]]
| subclassis = [[Neornithes]]
| infraclassis = [[Galloanserae]]
| ordo = [[Galliformes]]
| familia = [[Phasianidae]]
| subfamilia = '''Tetraoninae'''
| subfamilia_authority = [[Nicholas Aylward Vigors|Vigors]], 1825
| subdivision_ranks = [[Genera]]
| subdivision =
''[[Bonasa]]''<br />
''[[Falcipennis]]''<br />
''[[Centrocercus]]''<br />
''[[Dendragapus]]''<br />
''[[Lagopus]]''<br />
''[[Tetrao]]''<br />
''[[Tetrastes]]''<br />
''[[Tympanuchus]]''<br />
and see text
| synonyms =
Tetraonidae <small>Vigors, 1825</small>
}}

'''Grouse''' {{IPAc-en|ˈ|ɡ|r|aʊ|s}} are a group of birds from the [[order (biology)|order]] [[Galliformes]], in the [[family (biology)|family]] [[Phasianidae]]. Grouse are frequently assigned to the subfamily '''Tetraoninae''' (sometimes Tetraonidae), a classification supported by [[mitochondrial DNA]] sequence studies,<ref name=Gutierrez/> and applied by the [[American Ornithologists' Union]],<ref name=AOUlist/> [[ITIS]],<ref name=ITIS/> and others.<ref name=Boyd/> Grouse inhabit [[temperate]] and [[subarctic]] regions of the [[northern hemisphere]], from pine forests to moorland and mountainside,<ref name=EoB/> from 83° North ([[rock ptarmigan]] in northern [[Greenland]]) to 28° North ([[Attwater's prairie chicken]] in [[Texas]]).<ref name=Firefly/>

==Description==
Grouse are heavily built like other Galliformes such as [[chicken]]s.  They range in length from {{convert|31|to|95|cm|in|abbr=on}}, and in weight from {{convert|0.3|to|6.5|kg|lb|abbr=on}}.  Males are bigger than females&mdash;twice as heavy in the [[western capercaillie]], the biggest member of the family. Grouse have [[feather]]ed nostrils.  Their legs are feathered to the toes, and in winter the toes, too, have feathers or small scales on the sides, an adaptation for walking on snow and burrowing into it for shelter.  Unlike other Galliformes, they have no spurs.<ref name=Firefly/>

==Feeding and habits==
These birds feed mainly on vegetation&mdash;buds, [[catkin]]s, leaves, and twigs&mdash;which typically accounts for over 95% of adults' food by weight.  Thus their diets vary greatly with the seasons.  Hatchlings eat mostly [[insect]]s and other [[invertebrate]]s, gradually reducing their proportion of animal food to adult levels. Several of the forest-living species are notable for eating large quantities of [[conifer]] needles, which most other [[vertebrate]]s refuse.  To digest vegetable food, grouse have big [[crop (anatomy)|crop]]s and [[gizzard]]s, eat grit to break up food, and have long [[intestine]]s with well-developed [[caecum|caeca]] in which [[symbiosis|symbiotic]] bacteria digest [[cellulose]].<ref name=Firefly/>

Forest species flock only in autumn and winter, though individuals tolerate each other when they meet.  Prairie species are more social, and tundra species (ptarmigans, ''[[Lagopus]]'') are the most social, forming flocks of up to 100 in winter.  All grouse spend most of their time on the ground, though when alarmed, they may take off in a flurry and go into a long glide.<ref name=Firefly/>

Most species stay within their breeding range all year, but make short seasonal movements; many individuals of the [[rock ptarmigan|ptarmigan]] (called rock ptarmigan in America) and [[willow grouse]] (called willow ptarmigan in America) [[bird migration|migrate]] hundreds of kilometers.<ref name=Firefly/>

==Reproduction==
In all but one species (the Willow Ptarmigan), males are polygamous.  Many species have elaborate courtship displays on the ground at dawn and dusk, which in some are given in [[Lek (biology)|leks]].  The displays feature males' bright-colored [[comb (anatomy)|comb]]s and in some species, bright-colored inflatable sacs on the sides of their necks.  The males display their [[plumage]], give vocalizations that vary widely between species, and may engage in other activities, such as drumming or fluttering their wings, rattling their tails, and making display flights.  Occasionally, males fight.<ref name=Firefly/>

The nest is a shallow depressions on the ground, often in cover, with a scanty lining of plant material.  The female lays one clutch, but may replace it if the eggs are lost.  She begins to lay about a week after mating and lays one egg every day or two; the clutch comprises five to 12 eggs.  The eggs have the shape of hen's eggs and are pale yellow, sparsely spotted with brown.  On laying the second-last or last egg, the female starts 21 to 28 days of incubation.  Chicks hatch in dense, yellow-brown down and leave the nest immediately.  They soon develop feathers and can fly shortly before they are two weeks old.  The female (and the male in the willow grouse) stays with them and protects them until their first autumn, when they reach their mature weights (except in the male Capercaillies).  They are sexually mature the following spring, but often do not mate until later years.<ref name=Firefly/>

==Populations==
[[File:Bonasa-umbellus-001edit1.jpg|170px|thumbnail|right|A ruffed grouse in Canada]]
Grouse make up a considerable part of the vertebrate [[Biomass (ecology)|biomass]] in the Arctic and Subarctic.  Their numbers may fall sharply in years of bad weather or high predator populations&mdash;significant grouse populations are a major food source for [[lynx]], [[fox]]es, [[marten]]s, and [[bird of prey|birds of prey]].  However, because of their large clutches, they can recover quickly.

The three tundra species have maintained their former numbers.  The prairie and forest species have declined greatly because of habitat loss, though popular game birds such as the [[red grouse]] and the [[ruffed grouse]] have benefited from habitat management. Most grouse species are listed by the [[IUCN]] as "least concern" or "near threatened", but the [[greater prairie chicken|greater]] and [[lesser prairie chicken]] are listed as "vulnerable" and the [[Gunnison grouse]] is listed as "endangered". Some subspecies, such as Attwater's Prairie Chicken and the [[Cantabrian capercaillie]], and some national and regional populations are also in danger.<ref name=Firefly/>

==Sexual Size Dimorphism==

Male grouse tend to be larger than female grouse. This same pattern seems to hold true across all the species of grouse, with some difference within each species itself in terms of how drastic the size difference is. This phenotypic difference between the males and females is called [[sexual dimorphism]]. The hypothesis with the most supporting evidence for the evolution of sexual dimorphism is sexual selection. Sexual selection acts on male size, and the stronger this selecting force is, the larger increase in male size to a certain limit of size. Female size will increase correspondingly, and this is due to heredity, but not to the extent of the male size. This is because females that are smaller will still be able to reproduce without a substantial disadvantage, but this is not the case with males.<ref name=ssd />

Males and females also differ in behavior. In male grouse, there is the behavior of [[Lek mating|lekking]], which is when many males come together in one area and put on displays in order to attract females. In this situation, the females selectively choose among the males present.<ref name=Fiske>{{cite journal|last1=Fiske|first1=Peder|last2=Rintamaki|first2=Pekka|last3=Karvonen|first3=Eevi|title=Mating success in lekking males: a meta-analysis|journal=Behavioral Ecology|date=1998|volume=9|issue=4|pages=328–338|accessdate=19 October 2015}}</ref> There are two types of lekking that male grouse exhibit, exploded lekking, in which the territory is more expansive and has more variation, and typical lekking. Male grouse can also compete with one another for access to female grouse through territoriality, in which a male defends a territory in which there are resources that females need, like food and nest sites. <ref name=ssd /> These differences in mating systems are what account for the evolution of body size in grouse. Males of territorial species were smaller than those of exploded lekking species, and males of typical lekking species were the largest overall. <ref name=ssd /> The male birds that exhibit lekking behavior, and have to compete with other males for females to choose them, have higher sexual size dimorphism. <ref name=Soulsbury>{{cite journal|last1=Soulsbury|first1=Carl D|last2=Kervinen|first2=Matti|last3=Lebigre|first3=Christophe|title=Sexual size dimorphism and the strength of sexual selection in mammals and birds|journal=Evolutionary Ecology Research|date=2014|volume=16|pages=63–76|accessdate=1 October 2015}}</ref> This supports the hypothesis of sexual selection affecting male body size, and also gives an explanation for why some species of grouse have a more drastic difference between male and female body size than others. 

Sexual size dimorphism manifests itself differently between grouse and other birds. With owls specifically, the female is dominant over the male in breeding behavior. In owls and kestrels, it is typically females that are larger, while males are smaller in order to be more effective at hunting and defending the young. Females have the responsibility to feed the young with prey that the males have caught. <ref>{{cite journal|last1=Mueller|first1=H.C.|title=. The Evolution of Reversed Sexual Dimorphism in Owls: An Empirical Analysis of Possible Selective Factors|journal=The Wilson Bulletin|volume=98|issue=3|pages=387-406}}</ref>

==In culture==
Grouse are [[game (food)|game]], and hunters kill millions each year for [[food]], sport, and other uses. In the United Kingdom this takes the form of [[driven grouse shooting]]. The male [[black grouse]]'s tail feathers are a traditional ornament for hats in areas such as [[Scotland]] and the [[Alps]].  Folk dances from the Alps to the North American prairies imitate the displays of lekking males.<ref name=Firefly/>

==Species==
'''Genus ''[[Falcipennis]]'''''
* [[Siberian grouse]], ''Falcipennis falcipennis''
* [[Spruce grouse]], ''Falcipennis canadensis''
** Franklin's grouse, ''Falcipennis (canadensis) franklinii''
'''Genus ''[[Dendragapus]]'''''
* [[Dusky grouse]], ''Dendragapus obscurus''
* [[Sooty grouse]], ''Dendragapus fuliginosus''
'''Genus ''[[Lagopus]]''''' – ptarmigans
* [[Willow ptarmigan]], ''Lagopus lagopus''
** [[Red grouse]], ''Lagopus (lagopus) scoticus''
* [[Rock ptarmigan]], ''Lagopus muta''
* [[White-tailed ptarmigan]], ''Lagopus leucura''
'''Genus ''[[Tetrao]]''''' – black grouse
* [[Black grouse]], ''Tetrao tetrix''
* [[Caucasian grouse]], ''Tetrao mlokosiewiczi''
* [[Western capercaillie]], ''Tetrao urogallus''
** [[Cantabrian capercaillie]], ''Tetrao urogallus cantabricus''
* [[Black-billed capercaillie]], ''Tetrao Tetrao urogalloides''
'''Genus ''[[Tetrastes]]'''''
* [[Hazel grouse]], ''Tetrastes bonasia''
* [[Chinese grouse]], ''Tetrastes sewerzowi''
'''Genus ''Bonasa'''''
* [[Ruffed grouse]], ''Bonasa umbellus''
'''Genus ''[[Centrocercus]]''''' – sage grouse
* [[Sage grouse]], ''Centrocercus urophasianus''
* [[Gunnison grouse]], ''Centrocercus minimus''
'''Genus ''[[Tympanuchus]]''''' – prairie grouse
* [[Sharp-tailed grouse]], ''Tympanuchus phasianellus''
** [[Columbian sharp-tailed grouse]], ''T. phasianellus columbianus''
* [[Greater prairie chicken]], ''Tympanuchus cupido''
** [[Attwater's prairie chicken]], ''Tympanuchus cupido attwateri''
** [[Heath hen]], ''Tympanuchus cupido cupido'' ([[extinct]], 1932)
* [[Lesser prairie chicken]] ''Tympanuchus pallidicinctus''

==References==

===Footnotes===
{{reflist|refs=
<ref name=Gutierrez>{{cite journal |author1=Gutiérrez, R. J. |author2= Barrowclough, G. F. |author3=Groth, J. G. |title=A classification of the grouse (Aves: Tetroninae) based on mitochondrial DNA sequences |journal=Wildlife Biology |volume=6 |issue=4 |year=2000 |pages=205–212 |url=http://fwcb.cfans.umn.edu/research/owls/lit%20folder/gutierrez%20et%20al.%202000.pdf}}</ref>
<ref name=AOUlist>{{cite web|url=http://checklist.aou.org/taxa/ |title=AOU Checklist of North and Middle American Birds |publisher=American Ornithologists' Union|accessdate=2014-03-13}}</ref>
<ref name=ITIS>{{ITIS|id=553485|taxon=''Tetraoninae''|accessdate=2013-03-13}}</ref>
<ref name=Boyd>{{cite web|url=http://jboyd.net/Taxo/List2.html#phasianidae|title=Phasianidae: Turkeys, Grouse, Pheasants, Partridges |work=Aves – A taxonomy in flux|author=Boyd, John|accessdate=2014-03-13}}</ref>
<ref name=Firefly>{{cite book | last = Storch | first = Ilse |author2=Bendell, J. F. | year = 2003 | chapter = Grouse | editor = [[Chris Perrins|Perrins, Christopher]] | title = The Firefly Encyclopedia of Birds | publisher = Firefly Books | pages = 184&ndash;187 | isbn = 1-55297-777-3}}</ref>
<ref name=EoB>{{cite book |editor=Forshaw, Joseph|author= Rands, Michael R.W.|year=1991|title=Encyclopaedia of Animals: Birds|publisher= Merehurst Press|location=London|pages= 91|isbn= 1-85391-186-0}}</ref>
<ref name=ssd>{{cite journal|last1=Drovetski|first1=S. V.|last2=Rohwer|first2=S.|last3=Mode|first3=N. A.|title=Role of sexual and natural selection in evolution of body size and shape: a phylogenetic study of morphological radiation in grouse|journal=Journal of Evolutionary Biology|date=2006|volume=19|issue=4|pages=1083–1091}}</ref>
}}

===General===
{{cite book |author=De Juana, E. |year=1994 |chapter=Family Tetraonidae (Grouse) |pages=376–411 |editor1=del Hoyo, J. |editor2=Elliott, A. |editor3=Sargatal, J. |title=Handbook of the Birds of the World, Vol. 2. New World Vultures to Guineafowl |publisher=Lynx Edicions |location=Barcelona |isbn=84-87334-15-6}}

==External links==<!-- Auk113:811. MolPhylEvol20:149. SystBiol51:930. WildlBiol6:205. -->
{{Commons|Tetraoninae}}
*[http://ibc.lynxeds.com/family/grouse-tetraonidae Grouse videos] on the Internet Bird Collection
* P. Johnsgard, [http://digitalcommons.unl.edu/johnsgard/16/ "Etho-Ecological Apects of Hybridization in the Tetraonidae,"] ''World Pheasant Association Journal'' VII (1982), pp.&nbsp;42–57.

{{Meat|state=expanded}}

[[Category:Tetraoninae|*]]
[[Category:Grouse|*]]
[[Category:Birds of the United States]]
[[Category:Birds of Europe]]
[[Category:Zanclean first appearances]]