Red-tailed Hawk Tail Bands Used for Ageing?

26 October 2014

Can you age adult Red-tailed Hawks specifically as 2nd-year or older by their presence or absence of tail banding? I discussed this before, but was asked this question recently since it is the fall and hawk banders are catching lots of Red-tailed Hawks. The specific question asked to me was: Do Western Red-tails in their first adult plumage (2nd-year birds) often have multiple tail bands, and older Red-tailed Hawks (after-2nd-year) have unbanded tails? The truth is that tail patterns of adult Red-tails of every age vary from being completely banded to unbanded in no predominance. The only accurate way to age adult Red-tailed Hawks to a specific year is to determine if there is one generation or two generations of flight feathers (tail and wings). Body feathers may be helpful but it is often difficult to determine if old (from the previous molt) body feathers are juvenile or adult feathers.

If there is one generation of flight feathers, the bird is AHY (fall) or ASY (after January 1). One generation of flight feathers occurs on adult Red-tailed Hawks in their first adult plumage at times, but almost never on older birds. However, birds cannot be aged based on eye color or probability, so AHY or ASY are the only options for birds with one generation of feathers. Adult Red- tailed Hawks with 2 generations of flight feathers with the older retained feathers being juvenile are SY (fall) or TY (after January 1). Red-tailed Hawks with 2 generations of flight feathers with the older retained feathers being adult are ASY (fall) or ATY (after January 1). Sometimes it is possible to age Red-tailed Hawks 3rd or 4th-year in fall, but that is difficult without extensive practice, and inaccurate in certain cases because Red-tails older than 4 years old can show identical molt patterns to 3rd and 4th-year birds.

Remember, NEVER age adult Red-tailed Hawks to a specific year based on tail banding or any other pattern! Check out these Western Red-tails in their first adult plumage (labeled 2nd-year) that lack multiple tail bands, and these after-2nd-year birds with obvious tail bands...and thanks for reading.

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 At least 8 years old (known nester)
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 After-3rd-year (aged after January 1st)
 At least 12 years old (known nester)
 At least 11 years old (known year-round resident)
 At least 6 years old (known nester)
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