Tag Archive | red-tailed hawk

Harlan’s / Light Phase Red-tailed Hawk

Posted by Bob Lefebvre

Recently Terry Korolyk spotted an interesting hawk on Hwy 549 just west of Hwy 773, south of Calgary.  Terry says it is an intergrade Harlan’s light phase Red-tailed Hawk.

Terry says:

Thought some Birds Calgary viewers might like to see what this bird looked like. The underparts are obviously a mix of both subspecies. The underside of the tail is obviously white with duskiness near the tip. The upperside of the tail was, in reality, white with a reddish subterminal band and 2 narrower wavy reddish bands adjacent to that.

Photographed by Terry Korolyk on April 6, 2012.  Click to enlarge.

To fully appreciate the bird in the photo, look at images of adult Harlan’s Hawks and of adult Eastern Red-tails, then look at my bird again. Rather than blackish underparts with a white streaked throat like a Harlan’s Hawk, or, rather than having white underparts with a strongly streaked belly like an Eastern Red-tail, you have a bird with underparts markings that meet in between. The upperparts are clearly blackish like a Harlan’s Hawk, but they also have that Eastern Red-tail brownish cast. The tail was white like a Harlan’s Hawk, but, rather than having a dusky tip, it had 3 narrow wavy reddish lines there indicating normal light-phase Eastern Red-tail association.

As Terry says, the usual Red-tailed Hawks here are the Eastern subspecies, and “Harlan’s” Hawks are considered to be another subspecies of Red-tailed Hawk.  At one time, Harlan’s Hawk was considered to be a separate species entirely. Intergrades like the one above indicate that they are varieties of one species (many people believe that Harlan’s is a separate species; perhaps genetic testing will settle this question).

The Harlan’s Hawk is very different from all other Red-tailed Hawk subspecies.  In both its dark and light forms it has black and white plumage, lacking the reds and browns of other Red-tails.  The tail, however, can have a wide variety of patterns.  Harlan’s Hawk breeds in Alaska and northwestern Canada and winters on the southern great plains.  We see them occasionally in Calgary in the winter months, when most other Red-tailed Hawks are absent.

Wintering blackbirds in Texas

Winter leaps upon us in a flash. One minute, it seems, it is a very distant shape looming faintly on the horizon. Suddenly, before we know it, winter has struck, leaving us wondering where the summer went. In Texas, the same seems to happen with wintering birds. One day, only the year-round residents who call Texas home can be seen. The next day, countless wintering birds of all shapes and sizes are everywhere, confusing even the most attentive eye.

Countless blackbirds flock together during the winter

On a recent trip to Brazos Bend State Park here in Texas, about an hour southwest of Houston, we observed some spectacular flocking in action. Literally thousands upon thousands of blackbirds; Red-winged Blackbirds, Brown-headed Cowbirds, Common Grackles and European Starlings congregating on some farmer’s fields. They swarmed and swirled, seemingly in perfect coordination, lifting off and landing as a unit. And yet, this is not a sight you can readily behold on these bird wintering grounds. You don’t see flocks of thousands of these species doing this in the summer, so why do they do it in the winter???

These blackbirds have quite a few reasons for doing this in the winter but these flocking habits also have numerous downsides. First of all, on the positive side, foraging is greatly improved by the large flock as opposed to a single bird or a small group. The more eyes you have working together, the easier it is to find food! More eyes can also mean more safety from would-be predators, and trust me, there are a lot of them!

This brings us to one of the downsides of wintering flocks. Predators. Lots of them. Where there is food, there are consumers, waiting to, well, consume the food. Raptors see these blackbirds as one huge buffet just waiting to be sampled. In a small farmer’s field, we counted up to 20 raptors: about 10 Caracaras, many Red-tailed Hawks, several White-tailed Hawks, a Turkey Vulture and a couple of Northern Harriers, all exploring the delightful opportunity of a full stomach all winter long. If these hawks were to stick with the group of blackbirds, they could potentially always find one or two to pick off from the pack. The more birds in a flock, the more noise and commotion they make, rendering them easily visible targets.

Large concentrations of any living thing invariably bring with them two other depreciating factors; disease and competition. Avian diseases can be spread very quickly in such large flocks and may sometimes ravage a great portion of the local species. More birds might find better food sources but if there isn’t enough to go around, there simply isn’t enough. Weaker, slower and sick birds often will be the first to go hungry as they cannot compete with the healthier individuals.

It was definitely a neat sight to behold, especially when a raptor would plunge into the center of the throng, sending up explosions of blackbirds. One of the White-tailed Hawks that we spotted, an immature, had a very full crop (a muscular pouch near the throat used to store food), showing us that it had been eating well recently.

In the end, the advantages of these congregations greatly outweigh the disadvantages and it is a bewildering sight that will continue to captivate many a fortunate observer.

Posted by Matthew Sim

Fish Creek Park Birding

I had a very slow birding summer, with a knee problem that kept me out of the field and off my bike for three months.  But now my knee is better and I am back birding with Gus Yaki and the Friends of Fish Creek Society.  I went out twice with this group to the Hull’s Wood/Sikome/Lafarge Meadows area in mid-September.  Here are some pictures from those trips (click on the pictures to enlarge them).

Two Double-crested Cormorants, and on the right, an Osprey, silhouetted against the rising sun.

A cormorant dries its wings.

Double-crested Cormorant, this time with the light on the right side of the bird.

The Osprey perched in a tree.

Red-tailed Hawk in flight.

Northern Flickers.

Greater Yellowlegs, in one of the ponds by highway 22X.

We found a single Wood Duck (centre) hanging out with the Mallards.

Great Blue Heron on its usual rock.

Juvenile Bald Eagle.

This Cedar Waxwing was picking insects out of a spider web high in a tree.

American Kestrel.

Killdeer on the pond.

Killdeer on the river.

Common Raven calling near where they nested in Lafarge Meadows.

Finally, there is this bird, which we found sitting on a path that runs from the Sikome boat launch parking lot to the river.  I’ll tell its story next week.

Posted by Bob Lefebvre

Bird Profile: Red-tailed Hawk

Chances are you have seen this species before; this large hawk is one of the most widely distributed, numerous and commonly observed raptors in Canada. With a wingspan of up to 1.4m (58”) the Red-tailed Hawk is a highly variable buteo; soaring hawks that have wide tails and long, broad wings. Circling high up in the air, the Red-tailed Hawk can see mice scurrying about on the ground from 30 m (100ft) up .

This particular hawk in the photo appears to have done just that; he saw a mouse and then caught it, bringing the unfortunate rodent away to eat it, flying right over my head in the process of carrying off the mouse.

As mentioned before, the Red-tailed Hawk is a highly variable hawk with at least 14 recognized subspecies; ranging from the dark ‘Harlan’s Hawk’ to the ‘Krider’s Hawk’, a very pale subspecies of the Red-tailed Hawk.

Red-tailed Hawks love woodlands near open country; therefore, their habitat is diverse and they can be seen almost anywhere in Calgary. In summer, we tend to see light-colored morphs of the Western calurus the most and in migration and winter, we usually see dark morph ‘Harlan’s Hawks’. Also, in the southern part of Alberta, we have some krider’s Red-tailed Hawks. However, no matter what subspecies you see, they are still very impressive, especially when you get a good look at those talons!

Posted by Matthew Sim