For the 56,646 species in the Class Aves (Birds), we average 272.97 observations each in our database; for the Hairy Woodpecker, we have 520 observations. Compared to other species in this Class, this species is somewhat common.
A two-sample t-test can be used to determine whether the trend in observations of the Hairy Woodpecker is the same as the trend in observations of Aves. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=17.861, p<0.001)
How do observation rates of the Hairy Woodpecker differ from those of Aves? To answer this, we examined the percentage of observerations for Aves that were observations of the Hairy Woodpecker each year. We then correlated this percentage with observation year. If observations of the Hairy Woodpecker are becoming more common relative to other species of Aves, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is negative (r=-.7), with a negative slope (m = -.002), suggesting that the Hairy Woodpecker may be in decline relative to other species of Aves. This correlation is statistically significant. (F = 22.7, p<.05)
The scatter chart to the right shows the percentage of all observations for Aves each year that were observations of the Hairy Woodpecker.
History:
1988-Lower Risk/least concern (BirdLife International 2004)
1994-Lower Risk/least concern (BirdLife International 2004)
2000-Lower Risk/least concern (BirdLife International 2000)
Justification
This species has a large range, with an estimated global extent of occurrence of 13,000,000 km². It has a large global population estimated to be 9,400,000 individuals (Rich et al. 2003). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Face:white with black marksEye Ring: red patchMalar: black markPostocular Stripe: blackBill:blackLength: longNeck:Nape: blackBody:Underparts: whiteTail:black except that 3 outer feathers on each side are white.
Size/Age/Growth:
About 8.5 to 10.5 inches long, with a wingspan of 15 to 17.5 inches. Adults weigh about 2.5 ounces.
Picoides villosus Recordist: Doug Von GausigDate Recorded: February 22, 1999 Copyright Holder: NatureSongs.com Permissions for Use: Read this
Picoides villosus Recordist: Doug Von GausigLocation of Recording: Big Sur State Park, California Copyright Holder: NatureSongs.com Permissions for Use: Read this
Drumming in a Gambel Oak in the spring.
Recordist: Doug Von GausigCopyright Holder: NatureSongs.com Permissions for Use: Read this
Courting solo
Recordist: Tony PhillipsDate Recorded: May 02, 2005 Location of Recording: New Brunswick, New Jersey
Courting duet
Recordist: Tony PhillipsDate Recorded: May 02, 2005 Location of Recording: New Brunswick, New Jersey
Picoides villosus Recordist: John R. SauerCopyright Holder: John R. Sauer Permissions for Use: See here.
Alsop, Fred J. III. Birds of North America - Eastern Region. First American Edition. Smithsonian Handbooks. DK Publishing, Inc. 2001.
Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes 2003. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada.
BirdLife International. 2000. Threatened Birds of the World. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, U.K.
Ehrlich, P., Dobkin, D., and Wheye, D. (1988). The Birders Handbook: A Field Guide to the Natural History of North American Birds. New York: Simon and Schuster Inc. (info on clutch size, length of incubation, days to fledge and number of broods.)
Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc. (Length and wingspan info.)
BirdLife International 2004. Picoides villosus. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org . Downloaded on 21 October 2006.
Brands, S.J. (comp.) 1989-2006. Systema Naturae 2000. The Taxonomicon. Universal Taxonomic Services, Amsterdam, The Netherlands. Accessed October 3, 2006.
Global Biodiversity Information Facility. Accessed April 13, 2006. http://www.gbif.org Mediated distribution data from
provider.
Parker III, T.A., D.F. Stotz, and J.W. Fitzpatrick, and quot;Ecological and Distributional Databases for Neotropical Birds, and quot; in Neotropical Birds: Ecology and Conservation, by D.F. Stotz, T.A. Parker III, J.W. Fitzpatrick, and D.K. Moskovits (Chicago: University of Chicago Press, 1996). ISBN 0-226-64676-9.
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2004. Version 2005.2. USGS Patuxent Wildlife Research Center, Laurel, MD