Two Black-capped Chickadees meet on a branch. The familiar species is found year-round from Alaska to Newfoundland and from north- western California to the southern Appalachians and northeastern New Jersey. Photo by Steve Byland/Shutterstock
Our backyard chickadees are common, everyday birds that fill me with wonder.
It goes almost without saying that chickadees are cute and endearing, and it’s fair to call them friendly, too, and not just toward people with feeders. Northern warblers learn Black-capped Chickadee vocalizations long before they head south, distinguishing their mobbing calls near owls and sedentary predators (the dee-dee notes increasing as the threat level rises) from their high-intensity alarm call (a high-pitched see) given the moment the chickadee detects a fast-approaching falcon or hawk. Chickadees know the best spots to find food, water, and shelter and where predators lurk. They’re found in a wide range of habitats and have no objection to other songbirds and small woodpeckers associating with them. Small wonder warblers, vireos, kinglets, and other birds migrating through unfamiliar areas gravitate to chickadees.
Chickadees are among the first birds to discover new feeding stations and are fun to watch, but recognizing unmarked individuals is hard for us humans. They recognize one another, each flock organized into male and female hierarchies, older birds usually ranking highest. Daniel Mennill of the University of Windsor and others have learned that there are degrees of intensity within the black, white, and gray plumage colors, including some variations within the ultraviolet (UV) spectrum. Male Black-capped Chickadees have brighter white feathers, larger black patches, and greater contrast between adjacent white and black areas than females. The highest-ranking males have the darkest black caps and bibs.
To study hierarchy, community scientists as well as professionals record interactions among color-banded birds at feeders. Chickadees are ideal subjects: They’re easy for licensed banders to trap safely, and adults remain in a locality for their lifetime, easy to observe repeatedly at feeders or nest boxes. And they’re long-lived: at least three banded Black-capped Chickadees were re-trapped alive and released again by banders when they were more than 11 years old.
To survive frigid nights in northern Canada and Alaska, chickadees “turn down the thermostat” while roosting: Their body temperature drops an average of 20° F and sometimes much more. They awake shivering violently, that muscle action warming them to their normal 107° or so.
Minnesota’s all-time cold-temperature record, -60° F, was set in the town of Tower on February 2, 1996. One man who studied the forecast spent that night in a well-provisioned snow cave to boast that he survived the state’s coldest night ever, emerging at first light to news cameras and microphones. I watched coverage on the evening news, hearing chickadees calling and singing in the background, but not one reporter mentioned them.
Several studies have shown that in severe winters, chickadees with access to feeders have higher survival rates than those who do not. Even in northern winters, about half the food chickadees eat is animal — mostly insect pupae and eggs but also fat from suet and dead animals they encounter.
Laura photographed this Black-capped Chickadee, bearing a red color band and a federal aluminum band on its right leg and a PIT tag on its left leg in January 2009. Photo by Laura Erickson
How chickadees remember where they store food
When I worked at the Cornell Lab of Ornithology from 2008 to 2010, just about every chickadee I saw in Sapsucker Woods bore an aluminum leg band, one or two plastic color bands, and a PIT (passive integrated transponder) tag. Feeders throughout the area had RFID readers that recorded the time each tagged chickadee arrived and departed, giving researchers more comprehensive information about feeder use.
The Black-capped Chickadee’s ability to cache food and remember where hundreds of morsels are hidden is astonishing. Chickadee brains have a large hippocampus to store spatial memories. Medical researchers have learned that every autumn, a great many chickadee brain neurons die, to be replaced with new ones right when they are caching food at the highest rate. Chickadees may have memorized every crevice in a birch tree, valuable long-term information, but when the tree topples in an ice storm, they can delete those suddenly obsolete memories to make room for new ones.
Even the oldest chickadees add new memories every year, yet they hold onto some unused memories for a surprisingly long time. For years, I handfed mealworms to my backyard chickadees from my home office window, until I spent three winters in Ithaca, New York. The moment I cranked open that window on my return, two chickadees flew to my hand.
When I’m down and troubled, I can count on my backyard chickadees to engage my sense of wonder and restore my spirit.
