Lagerman Agricultural Preserve Open Sky Loop, June 12–with Aron Smolley

Grasslands are an iconic habitat of Colorado, although often overlooked since they lie in the shadow of the epic landscapes of Rocky Mountain National Park. However, grasslands and prairies account for a good percentage of Colorado natural areas. Sadly, in today’s day and age these crucial wildlife habitats are fragmented by roads and development, grazed by free-range cattle, and converted into farmland. Grassland birds happen to be one of the most imperiled groups of birds in the United States, having declined by around 40% since the 1960’s. Nevertheless, our native Colorado grassland birds seem to adapt well to the ever-changing landscapes, and Lagerman Agricultural Preserve provides rich habitat for an abundance of birds which is why we chose this location for the June 12th bird walk.

Great Horned Owl. Photo by Aron Smolley.

We had the largest group we’ve had in a while, after making a last-minute decision to allow the entire wait list to join. The first stretch of the Open Sky Loop is relatively uneventful, although we did get some nice views of western meadowlarks as well as a slow-motion Cooper’s Hawk flyover. There are little pockets of cottonwood trees and agricultural ditches along the trail, creating more diversity of habitat and we were lucky enough to find a Common Yellowthroat singing in one of the trees.

Further up the trail, by the ag pond, we stopped for a while and scoped out the surrounding area. Swainson’s Hawks and Red-tailed Hawks soared overhead, and both Eastern and Western Kingbirds chased insects from prominent fencepost perches. This provided an excellent opportunity to compare these species side-by-side, as well as generate some interesting discussion about bird behavior and adaptations. When Kingbirds catch insects in midair, this behavior is known as “hawking” and although it seems like a major acrobatic feat, to the bird it is as simple as opening the refrigerator door to us. This is because birds’ brains can interpret what they are seeing at a much higher-frame rate than we can, so they can react much quicker to the erratic flight pattern of an insect. We also enjoyed the thrill of watching one of the Kingbirds chasing other birds away from the area, and this territorial behavior is where they get their name.

Although our three target species (Bobolink, Dickcissel, and Blue Grosbeak) were nowhere to be found, we managed to get some soul-satisfying views of quite a few other species, including Cliff Swallows, American Goldfinch, and even a half-asleep roosting Great Horned Owl! Everyone got to view this majestic nocturnal raptor using the Novagrade phone adapter through the Zeiss Gavia spotting scope at 60x magnification. Other species of note were Osprey, American Kestrel, and Blue-winged Teal. For a hot day, and the trail being crowded with groups of bikers, I would say we didn’t do half bad.

 

1 Cooper’s Hawk

3 Swainson’s Hawks

2 Red-Tailed Hawks

Western Kingbird. Photo by Jamie Simo.

2 American Kestrels

1 Great-Horned Owl

1 Unidentified Raptor

Eastern Kingbird. Photo by Jamie Simo.

2 Western Kingbirds

2 Eastern Kingbirds

2 Blue-winged teal

1 Double-crested Cormorant

1 Great Blue Heron

1 Common Yellowthroat

X Mourning Dove

X Eurasian Collared Dove

X Black-billed Magpie

X Cliff Swallow

X European Starling

X Western Meadowlark

X Red-winged Blackbird

X Common Grackle

1 Great-Tailed Grackle

X American Goldfinch

Lagerman Agricultural Preserve, September 14, 2019–with Jamie Simo

Least Sandpiper in breeding plumage. Photo by Jamie Simo.

September is a great month to look for migrants and this past Saturday at Lagerman Agricultural Preserve didn’t disappoint on that count. We also welcomed our newest employee, Stephen Chang, to the FRBC team on this bird walk. Welcome, Stephen!

Baird’s Sandpiper in foreground and Least Sandpiper in background. Photo by Jamie Simo.

Unlike spring migration where birds are in a rush to find nesting territories, fall migration is a more leisurely affair, so we saw stopover species that breed farther north, Colorado breeders, and species that winter along the Front Range. In the stopover species category, we saw both Least and Baird’s Sandpipers. Least Sandpipers are the smallest shorebird species in the world and are long-distance migrants breeding in the arctic and wintering in Mexico and Central America. In addition to size, Least Sandpipers can be distinguished from the other small sandpipers classified as “peeps” by their yellow legs (the other four “peeps,” Western, Semipalmated, Baird’s, and White-rumped Sandpipers, have dark legs). In September, Least Sandpipers are still in breeding plumage and appear rusty with a couple of paler stripes down the back.

Baird’s Sandpipers are also long-distance migrants that breed in the arctic, although they travel even farther in winter than Least Sandpipers and fly all the way down to Chile and Argentina. Perhaps because of this they have long wings that extend slightly past their tails. They tend to look somewhat “scaly-backed,” especially juveniles, with dark-centered feathers on their backs edged with a paler tan. Their breasts are also tan with pale striping that doesn’t extend onto the clean white of their bellies and flanks.

Male Brewer’s Blackbird. Photo by Jamie Simo.

For species breeding in Colorado, we saw a number of Brewer’s Blackbirds. Brewer’s Blackbirds are often found in agricultural areas. Males are an iridescent black with a pale eye. The pale eye, lack of red shoulder patches, and thinner bill, distinguish them from the similar male Red-winged Blackbird. Female Brewer’s Blackbirds are brown with a dark eye and can be distinguished from the similar female Brown-headed Cowbird by being darker, larger, and having a thinner bill.

Finally, we were fortunate to see the first vanguard of several species that winter in our area, including the Ring-necked Duck. Despite being named for the ring around their neck, which is usually only visible at close range, Ring-necked Ducks have grey bills tipped with black and ringed with a band of white. Both males and females have peaked heads. Females are brown with a darker brown “saddle” on their backs and a white patch near the base of the bill. In non-breeding plumage, males can be picked out from females by their dark breasts, darker heads, and yellow eyes.

Male and female non-breeding Ring-necked Ducks next to American Coot. Photo by Jamie Simo.

In all, we saw 28 species. Join us next month at our Boulder location when we check out Barr Lake State Park and visit Bird Conservancy of the Rockies’ banding station.

Lagerman Agricultural Preserve, Sep 14, 2019
28 species (+1 other taxa)

Canada Goose 16
Blue-winged Teal 4
Cinnamon Teal 1
American Wigeon 24
Mallard 6
Green-winged Teal 2
Redhead 3
Ring-necked Duck 3
Ruddy Duck 3
Pied-billed Grebe 5
American Coot 12
Killdeer 6
Baird’s Sandpiper 4
Least Sandpiper 2
Short-billed/Longbilled Dowitcher 7
Ring-billed Gull 57
Double-crested Cormorant 13
American White Pelican 2
Great Blue Heron 2
Turkey Vulture 2
Osprey 1
American Kestrel 2
Say’s Phoebe 2
Barn Swallow 11
Lesser Goldfinch 3
American Goldfinch 2
Vesper Sparrow 4
Western Meadowlark 4
Brewer’s Blackbird 6