CHATFIELD STATE PARK — Warmer-than-average winter weather has enticed warblers, gulls and other birds rarely seen in metro Denver this time of year.
Now lingerers that rely on insects may be doomed by dropping temperatures.
Among at least 104 bird species spotted as of last week as Audubon Society and Denver Field Ornithologists counting crews fanned out statewide for the annual winter count are:
• Bonaparte and five other gulls seen at Chatfield Reservoir.
• A curve-billed thrasher confirmed in Denver’s Red Rocks Park.
• Ovenbird and palm warblers identified along Fountain Creek southeast of Colorado Springs.
• Eastern Phoebe flycatchers feeding at Bonny Reservoir north of Burlington.
• A Western grebe trolling on Chatfield Reservoir.
Bird-count data running back 57 years in the Denver area — a 15-mile-diameter circle encompassing Chatfield, Bear Creek and Marston reservoirs — have proved particularly useful.
Government agencies unable to match the effort rely on this data when planning projects that affect the environment.
While full results aren’t compiled until February, count leaders say some trends continued. Geese still are multiplying, attracted to reservoirs and golf courses. Only about 50 geese were spotted in 1954, compared with about 10,000 this year, according to preliminary data.
Meadowlarks and ring-necked pheasants that need unsullied grasslands are disappearing. More than 500 meadowlarks were spotted in 1954. Only a dozen were seen last year. Nobody’s seen a ring-necked pheasant for years, said Joey Kellner, coordinator of the Denver bird count.
If temperatures drop and reservoirs freeze, birds that lingered because of temperatures at least 5 degrees above average will perish, Kellner said.
Unlike ducks and geese, most need insects and will starve in the cold.
“And, from an evolutionary standpoint,” he said, “that makes sense.”
Bruce Finley: 303-954-1700 or bfinley@denverpost.com
