Did I see a peregrine falcon?
One would think it would be difficult to mistake any other bird for a peregrine falcon because of its popularity. But surprisingly, it happens often. Mistakes can be made for many different reasons.
Below are some of the birds that have been misidentified as peregrines and the most likely cause.
Cooper's hawks are often mistaken for peregrines both in city areas and suburban
and rural backyards. It is not hard to figure out why when we compare the two.
There are several similarities.
First, both Cooper's hawks and peregrines are about the same size (15-20 inches
from head to tail). Their plumage is similar (brownish head and back of juveniles,
blue-gray head and back of adults). Both species prey primarily on birds they
catch in flight.
So, how can one tell the difference? In general, Peregrines, being a threatened
species, aren't exactly common anywhere in the state. Cooper's hawks, on the
other hand, can be quite numerous in urban, suburban, and rural habitats.
The main difference to look for when you see one of these birds perched is
to look at where the wing tips fall in relation to the tip of the tail (when
the wings are folded against the body). Cooper's hawks have shorter wings and
a long tail and so their wing tips will fall several inches shorter than the
tip of the tail.
Peregrines have long wings and a shorter tail and so their wing tips will be
as long or longer than the tip of the tail. This field mark is easy to see even
if the bird appears only as silhouette.
This main physical difference in the length of their wings is what separates
the two species in the way they hunt also. Because of their shorter wings and
long tail that acts as a rudder, Cooper's hawks can maneuver through trees and
shrubs after other birds they are chasing. Peregrines, because of their longer wings, cannot. They need wide, open spaces
to fly high above and dive down on their prey. So, if you have the typical backyard
with trees and bushes and think you have a peregrine falcon raiding your birdfeeder,
look again. Chances are it's the more common Cooper's hawk.
A small falcon known as the American kestrel is a cousin to the larger peregrine falcon. Kestrels (once called sparrow hawks) are commonly found in rural and urban habitats.
They are cavity nesters preferring to feed on mice, grasshoppers and the occasional sparrow. They exhibit a similar "mustache" mark of the peregrine. But, their much smaller size is what separates kestrels from peregrines. American kestrels reach a size of about 9-12 inches from head to tail while peregrine falcons are about 15-20 inches long. Some may think that a kestrel is a "baby" peregrine falcon but in reality, by the time peregrine falcons leave the nest they are full adult size.
This 9 inch-long bird looks anything but common so some may wonder how in the world could anyone mistake it for a peregrine falcon? The confusion probably stems from the peregrine's fame in urban areas where nighthawks also nest. Oftentimes, nighthawks that are just learning to fly will end up stranded on the sidewalk in a city.
When well-meaning people find such an odd-looking bird and they remember hearing about peregrine falcons in the city, they put two and two together and assume the nighthawk must be a falcon!
Here's another species that you wouldn't think could be confused with a peregrine falcon. The uncertainty occurs when one finds a pigeon with a leg band.
Again, due to the publicity surrounding peregrines and the fact that many falcons are marked with metal leg bands, sometimes people assume because a bird has a leg band that it must be a peregrine falcon. Actually, many different kinds of birds are fitted with leg bands usually for research purposes.
Most pigeons that have leg bands are racing/homing pigeons and the band is put on by the owner of the bird.