Did you know that red-tailed hawks don’t have red tails until they’re more than two years old?

In January Rachel Baer photographed this immature hawk dining at Oakmont’s Riverside Park.  You can see that his tail is brown with horizontal stripes.  Here’s how you know he’s less than two years old:

Adult red-tailed hawks have rusty red tails (click here to see) but, as Cornell  Lab of Ornithology explains, immature birds usually molt into adult plumage — including the red tail — at the beginning of their second year.

During their first winter (age 6 months) and second winter (age 1.5 years) they look like the hawk Rachel photographed.

Here’s the top side of his tail, brown and striped.

And the underside — white (not even faintly rusty) with faint brown stripes.

In the spring of their second year (age 2.0 years) red-tailed hawks begin to replace their brown tail feathers with red ones.  That summer their tails show both colors. Click here to see a red-tail with a half-red tail.

By their third winter (age 2.5 years) their red tails advertize their maturity.  They’re now full adults and ready to court in the spring.

Of course, there are always exceptions. Cornell’s Birds of North America Online says that 5-10% of immature red-tails can molt into adult basic plumage at age 1.

The “aging” rule works only 90-95% of the time.  😉

(photos by Rachel Baer)

(*) NOTE: Red-tailed hawks are widespread across North America and the subspecies look different.  This blog post describes the eastern subspecies of the red-tailed hawk, Buteo jamaicensis borealis.  (The click-through image of a red-tail with a partially red-tail is a dark western bird.)