Sargassum Birds
By Jim Stevenson
Sargassum
is a red algae that emanates in the Sargasso Sea in the
middle of the Atlantic Ocean. It drifts westward and south ofFlorida
before entering the Gulf of Mexico in spring. With it comes tens of
millions of tiny animals, from Sargasso Fish to marine invertebrates
such as sea cucumbers, crabs and shrimp - all the color of the
sargassum. Locals call it “seaweed” but the birds
call it a buffet. This stretch below was on Bolivar Beach and you can
see gobs of Laughing Gulls working the shallows for lunch.
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Let's look at some other birds that enjoy sargassum
piles.
This
Forster’s Tern is bringing a Sargasso Fish to his sweetie in
hopes she’ll accept his offer of love. Or lust. Note the
orange legs and bill of the Forster’s as well as the long
tail. Obviously this bird is in full breeding plumage, with the black
cap. Do you know why this isn’t a Common Tern?
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The
far northern Glaucous Gull was sitting at the edge of the
sargassum, probably not even knowing what it was. However, that
didn’t keep him from robbing other smaller gulls of their
catch. This bird is sun bleached but still lacks any dark pigment in
the primaries – a sure sign it’s not a Herring.
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This
Laughing Gull has a large Sargasso Fish and is deciding what to do
with it. You can see the “weed” and its little
round gas bladders that keep it afloat. This allows it to float and the
algal mass to photosynthesize. Plants give off oxygen and that helps
fill the bladders with the very gas animals need to breathe.
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This
Sandwich Tern has caught something from the sargassum that I
can’t identify (and I taught marine biology!). It appears
segmented – possibly a crustacean - but that’s all
I know. You can see the shaggy crest of the tern and theiryellow bill
tip. They often feed out deep with the Royals, so who knows what they
are bringing in.
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This
smart Black-bellied Plover is snatching up small crustaceans from
the fresh sargassum as his body putsthe finishing touches on his
alternate (breeding) plumage. Soon he’ll be in the Arctic,
sitting on eggs laid in the chilly tundra. Here the sun will warm his
black belly and the eggs will be brought to life that much quicker.
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This
Marbled Godwit (left) and Western Willet (right) forage among the
sargassum for tiny animals, almost a mirror image of each other.
Western Willets migrate along the Gulf shore on their way westward and
the bounty brought in by the sargassum gives them the nourishment they
need. Note just how “godwit-like” the Western
Willet is.
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Hiding
between the sea foam and sargassum is a changing plumaged
Dunlin, another of the Far North nesters. Protein from this smorgasbord
needs to get him to the extreme North and he would likely perish
without it. Dunlins and Sanderlings actually breed further north than
Alaska and are about the same size.
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The
Semipalmated Plover is our most common and widespread small plover,
nesting well inside the Arctic Circle. They have darker backs than
Piping or Snowy and lack the thick, black bill of the
Wilson’s
Plover. Like many of our birds, there is an Old World species that
looks much like our species, and one day there needs to be a book on
these birds.
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Here
is a fine female Wilson’s Plover foraging among the
sargassum.
Their pink legs and thick, black bill are distinctive and no small crab
is safe around their beak. There are less than 7000 of these southern
breeders and their habitat is being compromised more every day. They
are the onlyplover (besides Killdeer) that breeds on the UpperTexas
Coast.
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