Birding at the Chico

The Chico Basin Ranch is a major flyway for migratory birds, due to the abundant springs, lakes and bird habitat on the ranch. The ranch works closely with Rocky Mountain Bird Observatory and has over 300 birds on the ranch bird list. Many people come to the ranch in the spring and fall to bird.

Bill Maynard is one of birders that comes most frequently. When we asked him if he would keep the ranch birding journal, he was pleased and agreed to do it. Thank you Bill! Bill has taught high school biology, worked as a naturalist for the National Park Service and as a biologist for a variety of government agencies. He has also worked for the American Birding Association at their national headquarters in Colorado Springs. 

Click Here to download the Ranch Bird Checklist

Click Here to download the Birding Trail Map (4mb PDF)

Click Here to download the Ranch Dragonfly and Damselfly Checklist

State Bird
Lark Buntings, the state bird of Colorado, are migratory.  Before and post breeding, they are often seen in flocks feeding on the ground where seeds can be found.  In the fall, sunflowers often are abundant along roadsides where extra moisture from summer thunderstorms accumulates. At the Chico entrance road there are patches of sunflowers and as expected Lark Buntings were feeding at the edge of the road under the sunflowers there.  Their post alternate molt is apparent and most birds were in a basic plumage when males, females, and juveniles look mostly similar.  There were four Barn Owls at the banding station trees indicating they bred successfully somewhere nearby.  Two have been in the area all summer, often seen flying away before allowing me a good look.
Posted by Bill M. on 08/29/2011

Although Black-chinned Hummingbirds breeds in small numbers on the Chico most other species are only seen in migration and mostly viewed at hummingbird feeders.  Hummingbirds have iridescent feathers, in North American hummingbirds, those feathers are on the throat or hummingbirds’ gorget and are among the most specialized of all bird feathers. Only about a third, the tips, of each feather is modified for iridescence. Because the feathers overlap like shingles on a roof, an unbroken color pattern is seen. Unlike most coloration in bird feathers that is a result of pigments, in hummingbird gorgets, the iridescence results from interference coloration, similar to the colors seen in oil spilled in a puddle of water.  Because red wavelengths are longer than those at the other end of the spectrum (ROY G BIV) red on one end and violet on the other, reds are reflected, like on this Broad-tailed Hummingbird above, a common mountain species that migrates through the Chico.  On hummingbird gorget feathers, color-producing pigment platlets are densely packed on the surface of the feathers in 8-10 layers, tightly stacked, one on top of the other.  This feature gives hummingbirds the most intense iridescent feathers known in birds.
Posted by Bill M. on 08/20/2011

Two shorebirds, Wilson's Phalaropes,  were at headquarters pond today. We  learned in a May post that they are a beauty during spring migration, the female, not the male, the brightest in plumage during the breeding season because males sit on the nests incubating eggs.  After breeding, neither male nor female needs their bright plumages so both migrate to hypersaline lakes in the west to undergo a basic molt, gradually loosing their brightly colored feathers and replacing them with dull sand-colored ones.  These phalaropes, after migrating through the western states and Central America will spend the boreal winter along shorelines in Bolivia and Argentina. Their two close relatives, Red-necked and Red phalaropes spend their winter offshore eating plankton.
Posted by Bill M. on 08/19/2011

Butterfly Mimic
The viceroy butterfly looks similar to the most recognizable of all butterfly species, the monarch butterfly.  But they are different species.  Monarch larvae feed on milkweed plants of various species and obtain cardiac glycocydes, a poison the accumulates in their bodies, including adult butterflies, from eating the milkweed plant. Jays, including Blue Jay, will eat a monarch, but only once, throwing up the foul food item and avoiding them afterwards.  The viceroy butterfly is not poisonous, but its coloration mimics the monarch.  The jay that ate the poisonous monarch avoids both the monarch and the mimic, the viceroy.  The bright coloration of both species serves as a warning to all potential predators to leave them both alone.  This principal only works if the mimic, in this case, the viceroy butterfly, is less common in nature than the model, the monarch. Sounds simple but it is not.  The Black-headed Grosbeak, a migrant at the Chico, is one of the few species not affected by the poisons accumulated in the monarchs' bodies.
Posted by Bill M. on 08/19/2011

Migrant Black Terns
Of the world's tern species only a few of them are dark colored.  Black Tern is a fresh watter specialist in summer but they winter off coastal Central and South America in salt water.  During the breeding season (northern Colorado and north) they feed primarily on damselflies and dragonflies (see photo) as they do  in migration.  While most terns plunge-dive for food, Black Terns feed off the surface (photo).  The population of Black Terns has dramatically been reduced and they seem to select a wetland for breeding based on the structure and not on the condition of the marsh.  The low nests are often destroyed as a result of wind or changing water levels and renesting frequently occurs.  After breeding, Black Terns molt losing almost all of their black feathering before reaching their wintering grounds.
Posted by Bill M. on 08/12/2011

Swainson's Hawk Migration
Swainson's Hawk, smaller than the resident Red-tailed Hawks, was named for William Swainson from England.  They breed on the Chico, especially in isolated trees on the prairie where they often return in spring to a previously used nest.  They begin their southbound migration in August with some individuals traveling as far as 14,000 miles to the pampas of southern Argentina and southern Brazil.  Almost the entire world population exits from North America.  They likely travel farther in migration that any other raptor.  Most of the world population of Swainson's Hawks funnel through the Isthmus of Panama during migration where I have seen over 3,000 birds in a single flock. 

As breeders, as their small talons dictate, they prey on small rodents and lots of grasshoppers added to their diet.  During migration, which can last as long as two months, it is thought they only feed during the beginning of the migration period. A pair with young can usually be found near the remote areas of Black Squirrel Creek where there are at scattered plains cottonwoods.
Posted by Bill M. on 08/07/2011

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