Cedar Waxwing

Berries left on branches past their peak ripeness can begin to ferment naturally, a process that produces ethanol just as it does when fruit ferments in any other context, and cedar waxwings feeding heavily on such overripe fruit, particularly during late winter when fresher food sources may be scarce, can end up consuming a meaningful amount of alcohol in the process. Documented cases have shown flocks displaying visibly impaired coordination, including difficulty flying in a straight line or perching properly, and in rare, more serious cases birds have died from collisions or other accidents while intoxicated, though most recover without lasting harm once the fermented fruit passes through their system.

The small, bright red, glossy droplets found on the tips of some secondary wing feathers, which give the species both its common name and its genus name, are not actually made of wax but are formed from a red pigment called astaxanthin that the bird accumulates from certain berries in its diet, particularly introduced honeysuckle species in parts of its range. Research has found that the number and size of these waxy tips tends to increase with a bird's age, and there is evidence that potential mates may use the extent of this waxy tipping as one visual cue when assessing a partner's quality or experience.

This food-passing behaviour, in which one bird offers a berry or other food item to a neighbouring bird perched nearby, who may eat it or pass it further along a line of birds, is thought to serve a social and courtship function within flocks and potential breeding pairs. Passing food is a recognised form of behavioural bonding in several bird species, and in cedar waxwings it may help strengthen pair bonds between a male and female or reinforce social relationships within the tightly knit flocks the species is known for, since cedar waxwings are unusually social for songbirds and spend much of the year in cohesive, coordinated groups.

Its heavy reliance on fruit and berries, a food source that has actually become more available in many human-altered landscapes thanks to widespread planting of ornamental berry-producing trees and shrubs in suburban gardens, parks, and landscaping, has arguably benefited the species compared to birds more dependent on habitats or food sources being lost to development. Its highly nomadic, flexible foraging strategy, moving in large flocks to wherever fruit crops happen to be abundant in a given year or region, also makes it less vulnerable to localised habitat loss than species tied more rigidly to a single specific breeding or feeding habitat, helping explain its comparatively stable population trend.