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They may look like little blizzards, but those
fast-moving cloudlike formations over Lake Springfield aren’t
precipitation. They’re gulls, flying low over the water. There are 51 identified species of gulls in the world
— 28 in North America — and Springfield has played host to at
least 18 of them.
Telling species apart can be quite difficult.
Variations in plumage can be subtle, with whites, grays, browns, blacks,
and occasional pinks. Adding to the complexity, variations within a species
can be dramatic, depending on a bird’s age and hybrid can occur. To
correctly identify a member of a species, an observer must analyze the
bird’s size, shape, color of the back, wingtips, tail, legs, eyes,
and bill, as well as recognize the pattern on the wings, tail, and
underparts. Figuring out the stage of molt — when birds drop their
old feathers and grow new ones — sometimes helps. One does not merely
look at gulls, one studies them. People who specialize in studying gulls are known as
larophiles. Around here we’re a diverse group, including a firefighter from St.
Louis, a schoolteacher from Belleville, and a grocer from Peoria. Of the 18 species that have been recorded here, three
are the most common, although none nests here. Ring-billed gulls, the most
numerous, are present throughout the year but they are very migratory, and
only a few immatures stay for summer. They nest as close as Chicago near
Lake Michigan. Practically all of the species, save a few immature birds,
leave during the summer. The larger herring gull frequents Lake Springfield
mostly in the winter, and the much smaller Bonaparte’s gull stops by
during migration. Bonaparte’s gull nests, oddly, in abandoned
songbird nests in open coniferous forests.
Most gulls come to Lake Springfield during periods of
maximum ice, making gull-watching even more difficult. At times my telescope is so cold
that it sucks the heat from my eye, fogging the objective lens. But the dead of winter is also a time for rare
sightings. One such memorable occurrence took place on Jan. 1, 1991. I was
slipping and sliding on the ice near the dam when I spotted an unusual gull
flying fairly low toward me. In my haste to stop, I slipped and fell on my
back. With no time to get up, I raised my binoculars while still on my
back, just in time to see an immature ivory gull gliding over me. It flew
out to Lake Springfield and landed on the edge of the ice. I joined several
other observers, and we watched, photographed, sketched, and took notes on
the rarest bird ever recorded in Sangamon County. At the time, this was the
southernmost point at which an ivory gull had been seen. These birds
usually stay in the Arctic, where they follow polar bears, eating bear dung
or the scraps of seals the bears have killed. The ivory gull is more at
home on the Arctic ice floes than in the relatively warm environs of
central Illinois, and it soon left. Thayer’s gull epitomizes the shades of
difference displayed by gulls. Once, in the early 1970s, it took me two
days to identify one. Fortunately improvements in field guides — some
devoted only to gulls — and the Internet make identification easier.
Even gull taxonomists cannot decide whether it is a full species and, if
so, whether it is more closely related to the herring gull or the Iceland
gull. Part of the problem is that these birds breed north of the Arctic
Circle and studying them in their nesting colonies presents logistical
nightmares. In December 2007 I found a large northern gull with
white wingtips, called the glaucous gull, in its first-year plumage. It had
apparently hit one of the many high wires crossing Lake Springfield, for it
had a bloody spot on its right wing and could not fly. The gull steamed
around the lake for several days and then disappeared, perhaps into a cove.
Then, on Jan. 3, the day of the Springfield Christmas Bird Count, I saw it
first thing in the morning, sitting on the ice with other gulls north of
the beach house. Later that afternoon I decided to see whether it was still
there. It was — but it was the only gull there, because adult bald
eagles were standing on either side of it. Avian predators such as eagles make frequent passes
over flocks of waterfowl and other birds to find those that cannot fly or do not attempt to get
away. If they spot an incapacitated bird, they will single it out and try
to kill it for food — I had watched some eagles kill and eat a herring gull a
couple of weeks before. These eagles had cut the glaucous gull from the
flock, and I watched through my 60-power scope what I thought would be a
fight to the death out on the ice. One eagle stood in the gull’s way,
making sure that the gull did not walk away; the other eagle was the aggressor. It flew over and
grabbed the gull and threw it a few feet. The gull slid on the ice but took
the abuse stolidly.
Then the eagle flew and hovered just above the gull several times —
but the gull pointed its fairly large bill up at it, and the eagle backed
off. Predators cannot afford to have their wings or feet injured, because
they use them in hunting and cannot survive without them. The aggressor
eagle walked and slid over to the gull, flew up and grabbed the
gull’s head with its talons, and flapped higher with the gull
dangling by its head. I thought that this would be the end, but the gull
started biting the eagle’s feet and the eagle let go, dropping the
gull back to the ice. Several variations of this attack took place over the
next several minutes, at which time I took the opportunity to digiscope some long-distance photos.
The nonaggressive eagle flew off. The other eagle stood for what seemed
like a long time and glared at the difficult gull, which just sat there as
if trying to ignore the eagle. Finally the second eagle flew away as well.
I thought that perhaps the eagle had punctured the
gull’s body cavity with its huge talons and that it was going off to
wait until the gull became weaker and then come back. I had to leave to
continue my bird count, but the next day I was there at first light, and
the glaucous gull was still sitting on the ice, none the worse for wear. I
saw the gull for several days after that — still alive — the
fighter of eagles! The next time you cross the dam at the lake and you
see the “blizzard,” know that the world is an extremely varied
and complex place. I hope that it will always be that way.
H. David Bohlen works in the zoology department of
the Illinois State Museum.
This article appears in Mar 6-12, 2008.
