Shorebird Nesting Has Begun

After weeks of nest searching with little luck, the birds have finally decided that it’s warm enough and they are ready to start laying eggs. In previous years, we documented a record-breaking early nesting attempt by an American oystercatcher pair on March 10, but nesting typically start around mid to late March.   So, needless to say, as March ended and April began, with no discovered Wilson’s plover or American oystercatcher nests, we were ready.

Freshly laid Wilson's plover nest

Freshly laid Wilson’s plover nest

This will be the last of three field seasons for an ongoing research project with the objective of determining how habitat variables can be used to predict nesting location and nest success for American oystercatchers and Wilson’s plovers.  We are also investigating how different nest predators (avian, raccoon, coyote) might influence nest location and nest success, and will incorporate effects of sea level rise, and geological processes, such as inlet dynamics and shoreline change, as well.

During the first week of April, we’d found only one Wilson’s plover nest and several Killdeer nests.  But, as temperatures have risen and spring has finally settled in, nesting has started with vigor!  In the past two weeks, we’ve found 38 Wilson’s plover nest and 7 American oystercatcher nests!  Birds have set up territories and within those territories created scrapes- shallow depressions made by smoothing and kicking out the sand.  They can make several scrapes in a territory, and then the female chooses one and lays her eggs.  The eggs blend in so well with the surrounding beach that they are very difficult for predators (and researchers) to find.

American oystercatcher nest

American oystercatcher nest

Last week, we found one of the coolest nests I’ve seen in the three years I’ve been out on the beaches. This Wilson’s plover pair nested right inside an old horseshoe crab shell!  They will likely lay one more egg and then in about 25 days, hopefully the nest will hatch.

The best nest: A Wilson’s plover nest inside a horseshoe crab shell!

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Musical mysteries on LSSI

As a naturalist, I often get the question of whether I get bored giving the same tours over and over. The answer is definitely no! Little St. Simons Island is a very dynamic system–changing with the seasons, movement of wildlife, tidal events, etc. I am always picking up on something new!

Norm's Pond. Photo: Britt Brown

At the end of this summer, we discovered a mysterious sound coming from Norm’s Pond. Norm’s Pond is one of our constructed freshwater ponds, surrounded by wax myrtles and host to alligators, frogs, nesting wading birds, Common Gallinules, and roosting White Ibis among others.

On a visit to the pond, as the nesting birds were starting to disperse, we picked up on a peculiar sound, one that took us a few days to place. Our Sherlock Holmes instincts kicked in. First guess was a frog. However, being a small island surrounded by salt water, we have a fairly small repertoire of amphibians. So, we reviewed the frog calls of species found nearby, but no matches.

Next guess would be a bird, but over the course of the summer we became very familiar with the sounds coming from the rookery (and they were quite amusing!). We ruled out all of the usual suspects.

Our next clue surfaced when tucked into the wax myrtles, we spied a beige spot of feathers–an Anhinga chick! Upon closer examination, there were at least two nests with three chicks each in relatively the same location that Anhingas had attempted to nest earlier this spring.

Turns out, our mysterious sound was that of Anhinga chicks begging for food. Listen to some Anhinga sounds courtesy of the Cornell Lab of Ornithology.

We first noticed the chicks at the end of August, which is unusually late, and by the end of September we were watching the fledglings clumsily dance and fly from perches around the pond. Although this year’s first nesting attempt by Anhingas ended in predation, we are excited to see these have success and to solve our mystery!

 

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Naturalist Fact: Black-crowned Night Heron

Black-crowned Night Herons can be found year-round at Little St. Simons Island. These mid-sized wading birds received their name because they are most active during the evening hours, but they can be seen during the day as well. Black-crowned Night Herons are most easily recognized by their piercing red eyes, yellow legs, and black crown. To distinguish them from a Yellow-crowned Night Heron, note that Yellow-crowned Night Herons have a white or yellow crown, not black.

It is suspected that Black-crowned Night Herons forage at night because they are outcompeted in the daytime hours by larger wading birds. While they eat mostly fish, they have developed another interesting hunting strategy: they have been known to nest in the same sites as other herons and egrets, using their protection during the day, and preying upon the other nests at night. This picture was taken early one morning in the rookery at Norm’s Pond—it seems as though this Black-crowned Night Heron is demonstrating this fascinating behavior!

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It’s nesting time… with a special guest appearance!

Male (dark neck) and female (tan neck) Anhingas at Norm's Pond.

For the past couple of years, wading birds have set up a rookery at Norm’s Pond. This year the usual suspects in their stunning breeding plumage have already shown up.  There are at least four pairs of  Great Egrets who have already nested and are incubating their sky-blue eggs. The Snowy Egrets are in putting on a great show of courtship as they pick their mates. There are also some Tricolored Heron’s hopping about the branches.

The ones that have really gotten everyone talking are the Anhingas! Similar in appearance and ecology to the Double-crested Cormorant that is common here, the Anhinga is a rare visitor to our island. The Anhinga’s range extends from the coast of North Carolina through Texas. They prefer slow-moving freshwater habitats, presumably why we don’t see too many on Little St. Simons Island.

Like the Cormorant, the Anhinga is a dark water bird with a long slender neck. However, the Anhinga has a sharply pointed bill, and whitish/silver feathers on the top of its wings. When in their breeding plumage (like the ones at Norm’s Pond shown in the pictures) they have a brilliant blueish green ring around their eye.

Anhingas nest in small trees or shrubs near the water, and the male begins gathering nesting material before it has a mate. The pair at Norm’s Pond has a nest built, and we eagerly await the eggs, and about a month later, the chicks!

For more information on Anhingas (Anhinga anhinga) check out the Cornell Lab of Ornithology.

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