On a chilly, snowy Saturday we visited ten different small reservoirs in northern Adams and Weld Counties.  Additionally, we also managed to find a much appreciated Taco John’s in Greeley.  Given what a bone-chilling day it was we were pleased to record 62 species.  Of the species missed, such as Cackling Goose, Common Goldeneye, and Hooded Merganser, local numbers have recently diminished as many birds have already begun to migrate north.  Others, such as Chipping, Song, Vesper, and Savanna Sparrows were presumably hunkering down in sheltered environs out of our field of view.

However, despite these misses, we had numerous highlights including fourteen duck species and three species of grebes.  Also, of particular interest were the ten species of shorebirds that we got to observe from the gigantic American Avocets (11 oz) to the diminutive Least Sandpipers (0.7 oz).  It’s quite a contrast when they’re standing side by side.  And it was special to see two species whose bills are over 2.5” long – Long-billed Dowitcher and Wilson’s Snipe.

Then, there were our five gull species.  As with the small sandpipers this is a realm that should give qualms to all birders, and we can only hope that we were correct with our identifications.  Difficulties with identification arise from the fact that it takes gulls, depending on their size, from two to four years to obtain full adult plumage, and that whether we’re comparing juveniles of different species or adults, the distinctions are subtle.  It helps to begin with gaining some familiarity with Ring-billed Gulls which are by far our most common gull.  Weighing just over a pound they are considered an intermediate sized gull, though some larger species weigh over three pounds.  In addition to all the Ring-bills we saw we were fortunate to find a few smaller Franklin’s Gulls which were readily identified by their black hoods, dark gray mantles (back), and striking white eye-arcs.  And then, we had three white-headed species that are all larger than the Ring-bills.  California Gulls have a slightly darker mantle and the black-and-red spot on the bill is on both the upper and lower mandible. Herring Gulls, looking imperious, have a larger bill with a red spot on the lower mandible – our bird was a juvenile distinguished in part by its pale pink legs.  Lesser Black-backed Gulls also have a red spot on the lower mandible, but the significantly darker mantle and upper wings help to distinguish it.

Other highlights of the morning included the six Icterid (blackbird) species we got to see including Brewer’s Blackbirds, Great-tailed Grackles, and many Yellow-headed Blackbirds.  Finally, one of the real highlights of the day was getting to see a group of Western Grebes and ducks panic as they rapidly submerged and dove when a Peregrine Falcon went swooping over them.

We are now moving into the peak of migration so be sure to make time to get out and take in some of the action.

Chuck

Weld County Apr 20, 2024 
62 species
11 participants

Canada Goose  45
Wood Duck  2
Blue-winged Teal  4
Northern Shoveler  84
Gadwall  88
American Wigeon  42
Mallard  41
Northern Pintail  2
Green-winged Teal  38
Redhead  5
Ring-necked Duck  19
Lesser Scaup  72
Bufflehead  15
Common Merganser  2
Ruddy Duck  24
Pied-billed Grebe  4
Eared Grebe  3
Western Grebe  50
Rock Pigeon (Feral Pigeon)  4
Eurasian Collared-Dove  3
Mourning Dove  1
American Coot  35
Black-necked Stilt  11
American Avocet  38
Killdeer  34
Long-billed Dowitcher  7
Wilson’s Snipe  3
Wilson’s Phalarope  4
Lesser Yellowlegs  40
Greater Yellowlegs  3
Least Sandpiper  15
Semipalmated Sandpiper  3
Franklin’s Gull  5
Ring-billed Gull  1502
Herring Gull  1
Lesser Black-backed Gull  3
California Gull  10
Double-crested Cormorant  6
American White Pelican  51
Great Blue Heron  2
Northern Harrier  3
Bald Eagle  4
Swainson’s Hawk  15
Red-tailed Hawk  8
American Kestrel  4
Peregrine Falcon  1
Say’s Phoebe  5
Loggerhead Shrike  1
Black-billed Magpie  1
Horned Lark  25
Barn Swallow  1
Cliff Swallow  3
European Starling  9
American Robin  44
American Pipit  4
White-crowned Sparrow  9
Yellow-headed Blackbird  94
Western Meadowlark  9
Red-winged Blackbird  107
Brewer’s Blackbird  34
Common Grackle  13
Great-tailed Grackle  10