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| ==> Home :: Places :: Site Guide :: Northwest :: South Twin Lake |
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Situated in the open landscape of Iowa’s Prairie
Pothole Region, South Twin Lake (Figure 1) serves as a magnet
for waterfowl and other migratory birds. In fact, due to
significant duck and goose numbers documented here in recent
years, this glacial lake (and its associated marshes and woods)
was recently added to the state’s list of Important Bird Areas.
Diverse gatherings of birds are almost always found on the water
here during spring and fall, and the peak seasonal
concentrations of various ducks can be quite impressive at
times. South Twin also provides refuge to land-bird migrants
along its periphery, giving birders a variety of options during
a visit.
There are multiple lakeside access points off of Twin
Lakes Road (Figure 1.1), which itself follows closely along much
of the lake’s perimeter. Along the wooded northeastern shore
(just across from Twin Lakes Golf Course), roadside pull-offs
enable views of the marshy portion of the lake. Many geese,
including Greater White-fronted, Ross’s, Snow, and Cackling,
often congregate along the cattails throughout this section in
both spring and fall. Most of the expected dabbling ducks are
usually found here as well, making this a prime spot to look for
Cinnamon Teal among the many Blue-winged Teal and Northern
Shovelers. However, even if there aren’t any rarities to be
found on a given day, taking some time to tally and observe the
interesting behaviors of the assorted waterbirds here definitely
makes the stop worthwhile. At the south end of the lake, small boat ramps and
clearings (Figures 1.2 and 1.3) enable visitors to scan the lake
in its entirety, and to discover any birds that were blocked by
vegetation during initial searches. Although each spot is worth
at least a quick check, the westernmost of these southern
accesses is typically the best place to commence searches for
diving ducks, loons, and grebes out on the broader portion of
the lake. Although Pied-billed Grebe and Horned Grebe are most
likely to be seen, all six of Iowa’s grebe species have been
recorded at South Twin. With more consistent searching, the
rarer loons may be added to the site list as well. Sea ducks
like Surf, White-winged, and Black Scoters, and Long-tailed Duck
are probably annual visitors here. Patiently searching through
large rafts of divers in the fall is one key to finding scoters
and long-taileds, although you can readily find them
individually or in monospecific groups, too. The south side of the lake is also the foremost place
to observe gulls that are either in flight or resting on the
lake itself. During many of my fall visits to South Twin, most
of the gulls are absent mid-day but gradually return to the
water during the evening. Franklin’s Gull, one of the signature
species of prairie-lakes landscapes, visits South Twin in
migration and gathers in substantial numbers in late September
and early October. Iowa has an impressive list of gull species
overall, and sorting through flocks of the more widespread
species (e.g., Ring-billed Gull) increases your chances of
finding a more unusual visitor. In fall, it is also useful to scope agricultural fields
off the south end of the lake, as they frequently have
foraging/resting flocks of geese. This provides a means of
watching these birds without the disruptive heat shimmer seen
over bodies of water under certain conditions. Heading around the west side of the lake, you’ll
eventually come to a wide gravel pull-off at the north end
(Figure 1.4). This overlook––situated next to a steep,
cliff-like segment of shoreline––is a great place to investigate
the northern half of South Twin during the afternoon and
evening. With the sun at your back, you can serenely scan all of
the aforementioned marshy habitats that extend to the opposite
shore. Checking the vicinity of these marshes is also the best
way to detect herons, night-herons, egrets, bitterns, and other
shallow-water denizens. Shorebirds also frequent this area when
there are at least a few mudflats exposed along the edges. The narrow belt of trees and shrubs around South Twin’s
shoreline attracts woodland/edge migrants in season. Walking or
slowing driving along Twin Lakes Road can sometimes produce a
surprising list of Neotropical songbirds, particularly under
fallout conditions (i.e., the arrival of cold fronts in the fall
and strong storm systems in the spring). Kinglets, thrushes,
warblers, etc. are relatively easy to pick out as you move
through this restricted habitat, which is a one-of-a-kind
sanctuary for miles in each direction. Of course, when scoping
the lake for waterfowl, it isn’t unusual to become pleasantly
sidetracked by the songbird activities happening around you. These lightly wooded and brushy habitats regularly hold
Emberizids (native sparrows), too. I usually pause for a few
minutes to monitor the roadside songbird activities before
setting up my scope for waterfowl viewing. Although the
northeastern shoreline is the most productive in this regard,
opportunities for native-sparrow observations exist all the way
around the lake. Back at the northwest corner, a small wildlife area
(just across from the overlook) provides another concentrated
habitat for migrant songbirds. When conditions are right, this
is a great location to obtain direct, eye-level looks at
Harris’s, White-crowned, Fox, Swamp, Song, Lincoln’s, and
American Tree Sparrows, especially in October. The adjacent crop
fields offer a handy opportunity to scan for open-country
species like Horned Lark, American Pipit, Vesper Sparrow,
Savannah Sparrow, Lapland Longspur, and perhaps Smith’s Longspur
during migration. Back across the road at the north end of the lake, the
marshes and woods teem with vociferous assemblages of
blackbirds, which routinely number in the thousands. Such flocks
usually have a few Rusty Blackbirds in their midst in March,
April, and October. Brewer’s Blackbirds, which are much less
likely to join the big mixed-species congregations, have been
noted in the vicinity of the overlook, and probably take
advantage of the nearby plowed fields and feedlots. For sure,
birding along the edge of the road can allow you to see many
species with minimal effort. Furthermore, since this little
viewing location is right next to the overlook, you can bolster
your day list without adding many miles to your trip. RAPTORS Many of Iowa’s raptor species make appearances at South Twin during migration. Northern Harriers are customarily seen coursing over nearby fields and prairie patches. Merlin, Peregrine Falcon, Cooper’s Hawk, and Sharp-shinned Hawk are occasionally spotted in flight near the lake or perched in trees along it. Additionally, the South Twin vicinity can produce all of the various western Red-tailed Hawk types (dark-morph, rufous-morph, Krider’s, Harlan’s, etc.) that venture into the state. Goose and duck hunters frequent South Twin Lake, and pheasant hunters sometimes explore the adjoining fields. Therefore, like at many wildlife areas in Iowa, wearing at least some blaze-orange clothing during the corresponding hunting seasons is advisable. But again, much of the birding here is easily accomplished from the roadside, and there’s plenty of room for everyone to accomplish their outdoor hobbies.) © 2009 Iowa Ornithologists' Union |
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