Getting out and looking for winter raptors is not just something we do to pass the time until Spring migration comes along.  It is an activity to be anticipated and relished!  Yes, there are some raptors that aren’t around in the winter. Turkey Vultures, Ospreys, and Swainson’s Hawks are somewhere to the south of us, as are most of the Peregrine Falcons.  However, year-round we still have Sharp-shinned Hawks, Cooper’s Hawks, Northern Goshawks, and American Kestrels, and there are some species whose numbers increase in the winter:  Northern Harrier, Bald Eagle, Red-tailed Hawk, Ferruginous Hawk, Golden Eagle, and Prairie Falcon.  Additionally, there are two species that are here only in the winter: Rough-legged Hawk and Merlin.  The bottom line – winter is when the raptor watching is best!  And, because there’s such a good variety around, it’s when we get to embrace some major identification challenges because every one of these species has two or more plumage variations.  In fact, if my math is correct, among our 13 most expected winter raptors there are well over fifty different looks we could get due to differences in sex, age, molt, subspecies, and polymorphism (there can be light, dark, and intermediate color morphs exhibited by all ages).  Might want to keep that winter hip flask handy.

Fortunately for our Saturday outing we at least didn’t have to contend with any adverse weather, and we were able to get great, long looks at many birds.  So, what did we see?  For starters we had 23 Bald Eagles, which might seem like a lot, but if you’re a regular visitor to the Barr Lake area you know that it can often be easy to see twice that many out there.  There are three factors to consider with these diminished numbers.  One is that the lake is frozen over, so for the time being there are no fish available and Bald Eagles are primarily piscivorous.  A second one is that we are right at the time when pairs with established territories are starting to lay eggs, and increased territoriality is driving unpaired individuals to leave the area.  Thirdly, most of our Saturday birds were adults hence it may be that some juveniles have already commenced their migration northwards.  Generally, we know that by mid-March numbers start to decrease.

Moving on, Red-tailed Hawks are our most common winter raptor.  Better get your field guide out for this one.  Most of our Saturday Red-tails were light-morph western birds (look for the dark throat), but we did see one eastern light-morph individual (look for the white throat).  Then, we also saw an adult rufous-morph and a dark-morph – probably also an adult.  I’m not going to detail all aspects of these birds, but I encourage you to spend some time with your field guide(s).   We also had a really great look at an adult Prairie Falcon.

The highlight of the day for me was the wonderful looks we had of numerous Rough-legged Hawks.  Again, these guys are a true arctic species and are only here in Colorado in the winter.  They can be fairly-common, but generally it’s necessary to get out on the eastern plains to find them.  Overall, they are long-winged and long-tailed with a small bill and feet.  While Ferruginous hawks are going after prairie dogs and hares, and Red-tails are getting rabbits and mice, Rough-legs in the winter concentrate on voles.  Being a raptor of the tundra and prairie, when hunting they hover readily and habitually before stooping for a prey item.  The plumage on Rough-legs is highly variable, more so than any other buteo.  Roughly speaking (to coin a phrase), adults of both sexes have broad dark sub-terminal tail bands, a dark trailing edge to the wing, and a dark carpal patch.  Light-morph females and juveniles have a wide dark belly band, while the male is darkest across the upper breast.  Juveniles also have the dark carpal patch.  There’s far more to discuss about Roughies, but that’s enough for this round.  Each bird can be so individual that it’s a delightful puzzle to work through the identification of each one.

Enjoy your winter birds!  Chuck

Barr Lake and 112th, Feb 19, 2022
Number of Taxa: 34

400 Cackling/Canada Goose
5 Mallard
4 Common Merganser
38 Rock Pigeon (Feral Pigeon)
1 Mourning Dove
1 Killdeer
7 Ring-billed Gull
4 Northern Harrier
23 Bald Eagle
15 Red-tailed Hawk
9 Rough-legged Hawk
1 Ferruginous Hawk
1 Great Horned Owl
1 Downy Woodpecker
5 Northern Flicker
1 Prairie Falcon
3 Blue Jay
16 Black-billed Magpie
4 American Crow
8 Black-capped Chickadee
23 Horned Lark
1 White-breasted Nuthatch
49 European Starling
1 American Robin
20 House Sparrow
40 House Finch
23 Dark-eyed Junco
3 Dark-eyed Junco (Slate-colored)
4 Dark-eyed Junco (Oregon)
2 Dark-eyed Junco (Pink-sided)
26 White-crowned Sparrow (Gambel’s)
12 Song Sparrow
17 Western Meadowlark
820 Red-winged Blackbird