What causes beak deformities in birds?

Since the late 1990s, Alaskans have reported large numbers of beak deformities in Black-capped Chickadees and other species of resident birds. This disease, called avian keratin disorder (AKD), is characterized by debilitating beak overgrowth and other abnormalities of keratinized tissues. Affected birds have difficulty feeding and preening, and can suffer high rates of mortality.

The USGS has identified a new picornavirus (Poecivirus) as the most likely factor responsible for AKD. Current research is focused on confirming the role of this virus in the development of AKD and learning more about how it might be transmitted among wild birds.

Other types of beak deformities can be caused by a variety of factors, including:

  •      Contaminants
  •      Nutritional deficiencies
  •      Disease
  •      Parasites
  •      Blunt trauma
  •      Genetic abnormalities

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Date published: November 8, 2010

Deformed Beaks May Signal a Greater Environmental Problem

ANCHORAGE, Alaska ­– The highest rate of beak abnormalities ever recorded in wild bird populations is being seen in a number of species in the Northwest and Alaska, and scientists to this point have not been able to isolate the cause.

Attribution: Region 11: Alaska
Filter Total Items: 7
Black-capped chickadee with beak deformity
April 19, 2016

Black-Capped Chickadee with Beak Deformity

Typical beak deformity in a (Poecile atricapillus) affected by avian keratin disorder in Anchorage, Alaska

A Boreal Chickadee with a slightly longer upper beak than the lower beak
March 31, 2016

Boreal Chickadee with a mildly deformed beak

A Boreal Chickadee with a mildly deformed beak.

A Red-breasted Nuthatch
October 9, 2015

A Red-breasted Nuthatch captured at an Anchorage banding station

A Red-breasted Nuthatch captured at an Anchorage banding station

A Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is
April 13, 2015

Black-capped Chickadee with lower elongated and upper curved beak

A Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is  elongated and straight

A Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is
April 13, 2015

Black-capped Chickadee with lower elongated and upper curved beak

A Black-capped Chickadee with a severely deformed beak where the upper beak is elongated and curved down while the lower beak is elongated and straight

A little gray bird
September 7, 2014

Slate-colored Junco

A Slate-colored Junco on Middleton Island, Alaska.

A Black-capped Chickadee on a branch with a grossly deformed beak
May 31, 2004

Black-capped chickadee with a deformed beak

Black-capped chickadee with a deformed beak