Saturday October 14, 2023 Bird Walk to Lagerman Reservoir with Jamie Simo

October 18, 2023

On a perfect Saturday morning (we even had an eclipse to enjoy!) we set out on a leisurely walk around Lagerman Reservoir to see what birds we could see. Lagerman is usually busy all year, but particularly shines in fall and winter when waterfowl and raptors are the highlights. Right away we spotted a juvenile light-morph Ferruginous Hawk that had staked a claim on a power pole overlooking the nearby prairie dog colony.

Ferruginous Hawks, named for the rusty or “ferrous” (iron) color of the feathers on their legs and backs, are our largest hawk and primarily feed on prairie dogs. Juvenile light-morphs are less rusty than their adult counterparts with more spotting on their underparts.

We were also treated to several other raptors out hunting, including a couple of adult Bald Eagles, an American Kestrel, and a Northern Harrier. The Northern Harrier is the only bird of its genus, Circus, in North America. They breed and hunt in grasslands and marshes where they use their disc-shaped faces to locate rodents. The disc shape helps funnel sound to their ears, a characteristic they share with owls, though they aren’t closely-related.

Male Northern Harrier. Photo by Jamie Simo

In addition to raptors, we had an abundance of waterfowl on Saturday. Of particular note were several Eared Grebes, the only grebe species we encountered. In winter, Eared Grebes are mostly varying shades of grey, retaining only the red eyes from their spectacular breeding plumage. They often are easily confused with Horned Grebes, with several minor differences. While Horned Grebes have bright white cheeks, Eared Grebes’ cheeks are a dusky color that doesn’t stand out from the color of their faces or necks. A good mnemonic to remember this characteristic is Eared=smeared. Also, while Horned Grebes’ heads are squarish, Eared Grebes have somewhat lumpy heads with a peak toward the front of the head.

Non-breeding Eared Grebe. Photo by Jamie Simo

We were also treated to great looks at many ducks including, but not limited to, Northern Pintail, Redhead, Canvasback, and American Wigeon. A very successful walk!

Lagerman Agricultural Preserve–Lagerman Reservoir, Boulder, Colorado, US
36 species

Canada Goose  26
Northern Shoveler  7
Gadwall  2
American Wigeon  15
Mallard  12
Northern Pintail  6
Green-winged Teal  8
Canvasback  5     
Redhead  20
Ring-necked Duck  4
Bufflehead  5
Ruddy Duck  50
Eared Grebe  6
Rock Pigeon (Feral Pigeon)  13
American Coot  80
Killdeer  10
Least Sandpiper  1
Wilson’s Snipe  2
Ring-billed Gull  6
American White Pelican  2
Northern Harrier  1
Bald Eagle  2
Red-tailed Hawk  1
Ferruginous Hawk  1
Northern Flicker  2
American Kestrel  2
Say’s Phoebe  1
Black-billed Magpie  1
American Crow  2
European Starling  50
American Robin  1
American Pipit  12
White-crowned Sparrow  1
Western Meadowlark  12
Red-winged Blackbird  10
Brewer’s Blackbird  8


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