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Shorebird Team Shares Guide to Aging Chicks

June 26, 2023
newly hatched least tern chick sitting in sand

With July on the horizon, shorebird and seabird nesting season is starting to wind down! Most of the final renesting attempts will be occurring this month, which means you could be seeing shorebird and seabird chicks soon, if you haven’t already.

On Sanibel and Captiva, we currently have snowy plover (Charadrius nivosus) and least tern (Sternula antillarum) chicks of varying ages.

In case you see one and wonder how to tell how old that little bird is, we’ve to put together some identifying characteristics by age to help you figure that out.

Least Tern Chicks

After hatching, least tern chicks appear sand-colored, speckled, and without visible wings or tails — looking very similar to the eggs from which they just hatched. They are able to walk within hours of hatching, but will stay in their nest for a few days.

“After about two weeks, their downy fluff is replaced with light brown or gray, scaly feathers, and they are much more mobile,” said Shorebird Intern Jessie Macaluso. “They often venture outside of posted nesting areas, so if you’re near a colony, watch your step!”

Least tern chick stages of development

Three to four weeks after hatching, least tern chicks are able to fly in short bursts, and their body shape more closely resembles that of an adult. At more than four weeks old, juveniles can be distinguished from younger fledglings by the black stripe running through their eyes and around the back of their head. These juveniles are also identifiable by being more adept flyers.

When these non-reproducing adult birds that fledged the year prior enter their second year, they look similar to fledglings, but have smooth back feathers, and the black feathers around the eye do not extend to the bill. For a more detailed guide to least tern chick aging, click here.

Snowy Plover Chicks

Snowy plover chicks also start out sand-colored and speckled, but unlike least tern chicks, they waste no time staying put in the nest! You may see them running about on their disproportionately long legs hours after they hatch.

Snowy plover chick progression

“This notable difference is because snowy plover chicks are precocial; they’re born in an advanced stage of development and are able to forage for their own food,” said Shorebird Technician Aaron White. “Least tern chicks are altricial, which means they still rely on their parents for food until they are able to fly and feed themselves.”

After two weeks, snowy plover chicks are less “fuzzy” and more “scruffy” as their primary feathers start to come in. They become more adventurous, leaving the dune habitat to explore the shoreline.

After four to six weeks of development, the chicks look like slightly smaller, skinnier versions of their parents, minus the bold breeding plumage exhibited by mature adults. At this point, they are flight-capable and may be seen flying with their parents or siblings before venturing out on their own. For a more detailed guide to snowy plover chick aging, click here.


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