Bald birds and hairy caterpillars

Male Northern cardinal/ Photo by ©Maria de Bruyn.


By Maria de Bruyn

Lately, I’ve heard a few people wondering whether something is wrong with Northern cardinals they’ve seen. Usually, these state birds look gorgeous with the males’ vibrant, deep red hues and the females’ more muted brown tones highlighted by reddish hues.

Top left: male cardinal beginning autumn molt. Top right: male cardinal getting ready to replace head feathers. Bottom left: Carolina wren that lost all its tail feathers. Bottom center: wren with tail feathers growing in. Bottom right: wren with new tail feathers. All photos by ©Maria de Bruyn.

The past few weeks, however, we’ve been seeing quite a few bald cardinals. It’s not an attractive look and some people wonder if the birds are sick. That’s not the case — the cardinals are molting and replacing their worn feathers with fresh plumage.

Feathers are made up of keratin, the same material as human fingernails or hair. When they begin to wear down or are damaged, birds replace them. Sometimes they lose all their feathers in one area at once. It can be interesting to see their skin and ear holes revealed when it’s their head. A lack of feathers can be quite noticeable in Carolina wrens when they lose all their tail feathers at once.

Left: immature Eastern bluebirds. Right: adult Eastern bluebird. Both photos by ©Maria de Bruyn.

Among some bird species, the new offspring may look different from their elders and take some time to achieve their adult plumage. Eastern bluebird young are speckled and slowly achieve their blue back feathers and rusty breasts as autumn approaches.

European starlings at different stages of plumage change from lightly colored juveniles (top left) to dark, glossy adults with white spots and purplish highlights on black feathers (bottom right). All photos by ©Maria de Bruyn.

Other young birds, like European starlings, may undergo multiple appearance changes over several months. Their process of exchanging juvenile for adult plumage takes a lot of energy and perhaps, that’s why young starlings have such voracious appetites and raucous cries insisting that they be fed.

Top left: Io moth caterpillar. Top right: saddleback moth caterpillar. Bottom left: milkweed tussock moth caterpillar. Bottom right: banded tussock moth caterpillar. All photos by ©Maria de Bruyn.

While various bird species are getting ready to migrate south when they complete their autumn molting, we can see the caterpillars of various moths emerging and looking very pretty. However, it’s advisable to be cautious around these hairy bug beauties, as some are quite painful to touch. Venomous caterpillars inject poison or venom by stinging, while poisonous caterpillars transmit their defense by touching you. To avoid either possibility, it’s best to admire them without giving in to the urge to pick them up!

The photo above shows examples of such caterpillars of the “look and don’t touch ” category. The Io moth caterpillar doesn’t look too hairy, but its stinging spines can transmit a very painful venom. When touched, the cute saddleback moth caterpillar may cause a highly stinging inflamed rash. Sometimes this is accompanied by nausea. The beautifully colored hairs of the milkweed tussock moth caterpillar can cause skin irritation and handling these caterpillars can produce nausea, vomiting and allergic reactions. While not venomous, the banded tussock moth caterpillar has long yellow hairs that can trigger skin reactions such as rashes, especially in people with known allergies.

If you or your child is stung by a hairy caterpillar, try to begin treatment immediately. To pull out the hairs, repeatedly place tape over the site and slowly pull it up and off (not jerking it). Wash the skin well with warm, soapy water and apply a corticosteroid cream or baking soda and water paste to the area around the sting.

An ice pack may help reduce pain and inflammation at the sting site, while oral antihistamines may provide some relief. See an urgent care provider if the swelling persists or you have difficulty breathing.

Do enjoy discovering and watching the autumn caterpillars. And know that those scruffy birds you may be seeing will become attractive avians again soon.

Maria de Bruyn participates in several nature-oriented citizen science projects, volunteers at Mason Farm Biological Reserve and the Orange County Senior Center, coordinates a nature-themed book club, posts on Instagram ( and writes a blog focusing on wildlife at

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