Chickadees are small songbirds that are found throughout North America. In the fall, chickadees undergo several behavioral and physiological changes to prepare for the winter months ahead. Their behaviors and adaptations allow them to survive the harsh conditions of winter.
What happens to chickadees in the fall?
Several key things happen to chickadees in the fall:
Molting
Chickadees molt and grow new feathers in the fall. Molting allows them to grow an insulating layer of feathers to keep warm in the winter. Their feathers also become more dense. The molting process usually begins in late summer and continues into early fall.
Storing food
Chickadees spend much of the fall storing food to eat during the winter when food is scarce. They store food like seeds, berries, and insects in many scattered locations, then return to these sites to feed throughout the winter. Their excellent spatial memory allows them to relocate hundreds of storage sites.
Forming flocks
In the fall, chickadees form large mixed-species flocks with other small birds like nuthatches, woodpeckers, and kinglets. These flocks allow them to more efficiently locate food sources and provide increased protection from predators. The flocks break up again in spring when breeding begins.
Shifting ranges
Some northern chickadee populations migrate short distances south in the fall to avoid the harshest winter weather. Chickadees may then return to their normal breeding grounds in spring.
How do chickadees molt in the fall?
Molting is an important process that chickadees undergo in the fall to grow new, higher quality feathers. Here are some key facts about chickadee molting:
- The molt begins any time from late summer to early fall, usually going into September and October.
- Chickadees molt all their head feathers first, followed by their body feathers.
- The wing and tail feathers are molted last, often not until late October or November.
- Molting takes 30-40 days to fully complete. Chickadees replace roughly 2500 feathers.
- While molting, chickadees are vulnerable and tend to hide more than usual.
- The new feathers provide better insulation and waterproofing for winter.
When does the molt occur?
Molting generally begins in late summer, anywhere from July to early September depending on the region and species. It continues into early fall, finishing by late October or early November in most areas.
Which feathers are replaced?
Chickadees replace all of their head feathers first before moving onto the body feathers. The wing and tail feathers are replaced last. Primary wing feathers may not be replaced until late October.
How long does molting take?
A complete chickadee molt takes around 30-40 days from start to finish. Some sources estimate they replace 2,500 to 3,000 feathers during the molt.
What are the effects of molting?
Molting leaves chickadees vulnerable and weak while growing new feathers. They tend to hide more than usual and may have difficulty evading predators. Their foraging and feeding abilities are temporarily impacted during the molt.
How do chickadees store food in the fall?
Chickadees have an excellent spatial memory that allows them to cache hundreds of food items in scattered locations and relocate these sites throughout harsh winter months. Here are some key facts about their food caching behavior:
What foods do they cache?
Chickadees store high-energy foods including:
- Seeds from plants like birch, elm, sumac, sweetgum, and hemlock
- Acorns and nuts from trees like oaks, beech, and pines
- Berries from shrubs and vines
- Insects like beetles, caterpillars, spiders, and larvae
How do they find cache sites?
Chickadees search out cache sites in their territory, looking for natural crevices and cracks in trees, fencerows, stumps, and rocks that provide hiding spots. They also dig holes in rotted wood. Sites are chosen to be inconspicuous.
How many items do they cache?
Chickadees make thousands of caches every fall. Studies have found they can cache anywhere from 3,000 to 6,000 items or more by the end of fall. Their spatial memory allows them to relocate these sites all winter.
How do they relocate caches?
Chickadees primarily rely on spatial memory based on visual landmarks to relocate caches. Their hippocampus, which handles spatial memory, actually grows in fall and winter to accommodate more cache sites. Even when cache sites are moved, chickadees can quickly adapt.
Food | Caching Adaptations |
---|---|
Seeds | Carry in bill and tuck into crevices in bark, holes, fencerows |
Acorns | Jam into cracks and holes, hammer into place with bill |
Berries | Quickly swallow and regurgitate for storage in cavities |
Insects | Pack into rotted stumps and holes |
How do chickadees form flocks in fall and winter?
Chickadees form mixed-species flocks with other birds in fall that persist through winter. These flocks provide several benefits:
What species flock together?
Chickadees often join flocks with:
- Nuthatches
- Woodpeckers
- Creepers
- Kinglets
- Warblers
- Titmice
Flocks can contain anywhere from a dozen to over 50 birds. Chickadees and nuthatches are usually dominant members.
Why do they flock together?
The benefits of mixed flocks include:
- Finding food sources
- Avoiding predators
- Sharing roosts sites
- Accessing new habitats
Food finding is more efficient in flocks and more eyes watch for predators. Flocks can cover and access broader areas.
How are flocks organized?
Flocks have a definite social hierarchy, with dominant chickadees and nuthatches leading activities. Birds share information about food sources. Chickadees give distinctive calls, like gargling notes, to attract flock members.
When do flocks break up?
Flocks start to dissipate in late winter as food becomes more available and the breeding season approaches. Most fully break up by April or May as birds establish nesting sites.
Do chickadees migrate or move around in fall and winter?
Some chickadee populations migrate short distances in fall, while others remain in the same areas year-round. Here are some movement patterns:
Carolina chickadees
Carolina chickadees in the northern parts of their range migrate south by up to a few hundred miles in fall. More southern populations remain resident year-round.
Black-capped chickadees
Black-capped chickadees at higher latitudes and elevations migrate short distances to lower areas in fall. Birds farther south are mostly non-migratory.
Boreal chickadees
Boreal chickadees make altitudinal migrations, moving to lower elevations in fall to escape harsh montane winter conditions. Their winter range expands southward.
Mountain chickadees
Mountain chickadees that breed at high elevations migrate downslope on mountain ranges in winter, sometimes intermixing with flocks of black-capped chickadees at lower elevations.
Chestnut-backed chickadees
Chestnut-backed chickadees do not make major migrations or movements. They are residential year-round throughout their range along the Pacific Coast.
How do chickadees survive winter?
Chickadees are well adapted to survive harsh northern winters despite their small size:
Use of microhabitats
Chickadees roost in cavities or dense conifers that provide insulation and protection from wind, snow, and cold. They may huddle together for warmth.
Winter fat storage
Chickadees grow heavy fat reserves in fall that provide energy and insulation during winter when less food is available. They may increase body fat by up to 50%.
Fluffed feathers
Chickadees fluff their feathers out for maximum insulation. Their dense winter feathers trap more body heat.
Nightly hypothermia
Chickadees lower their body temperature by up to 10-12 °C each night to conserve energy. This controlled hypothermia reduces their energy needs.
Cached food
Stored food provides reliable energy sources when winter foraging is more difficult. Chickadees can gain 25% of winter energy from caches.
Mixed flocks
Flocks provide social benefits like shared roost sites, predator vigilance, and efficient food finding that help chickadees survive.
How do changes in fall weather affect chickadees?
Shifting fall weather patterns due to climate change may impact chickadees in the following ways:
Warmer temperatures
If temperatures remain warmer later into fall, molting and winter fat storage could be delayed, leaving chickadees vulnerable when cold weather eventually arrives.
Extreme cold snaps
Early cold snaps before adequate fat reserves are developed could cause chickadees to starve or lose condition if caches are not fully stockpiled.
Altered precipitation
Changes in rainfall could affect food supplies like insect availability. Drought could reduce caches of seeds, nuts, and berries.
Loss of synchronized timing with food sources
If warming temperatures cause mismatches between chickadees’ preparation for winter and ripening of food sources they depend on, it could hamper their ability to create caches.
Range shifts
Warming trends may cause northern chickadees to shift their range farther north. More southern species may expand northward.
Influx of diseases and parasites
Warmer fall weather could increase disease-carrying mosquito activity or allow southern parasites to expand northward into chickadees’ range.
Conclusion
In fall, chickadees undergo an intriguing transition to prepare for winter’s challenges. Molting into warmer feathers,caching abundant food, forming social flocks, and migrating short distances allow chickadees to thrive in harsh northern climates all winter long. Their complex fall behavior highlights how even small birds are finely tuned to the seasons. While climate change introduces new risks, chickadees’ remarkable adaptability equips them to persist as the seasons shift. Their hustle in fall ensures they will continue brightening winter days with their lively presence for years to come.