I did not intend to write so much when I started. So let's end with this one.
In the last installment, I discussed the moist-soil technique of waterfowl management, which produces much of the shorebird habitat at CA's that Missouri birders frequent. An impoundment is allowed to grow up with smartweed and other annuals that ducks like and flooded for the hunting season. It then remains underwater for the winter or is reflooded by intentional management or spring rains when the ducks come back in March or April. By the time the shore bird migration really gets going in mid-April, the vegetation  in the impoundment has been under water for a long time and has disintegrated. As a result, when the impoundment is drawn down or evaporates, the exposed habitat is usually covered with remnant dead vegetation and/or muck. Only some shorebirds -- e.g. especially Wilson's Snipe, Yellowlegs and Pectoral Sandpipers, like this stuff. Other kinds of shore birds like a sandier feeding area, or at least a more open area lacking remnant vegetation to feed and rest. To see the whole range of shorebird species, the birder needs to find some of the more open, less vegetated, less covered-with-black-muck, habitat. That can be hard to do, but there is usually some of it around.
Here are some of the more common species, their time of migration and their preferences:
Wilson's Snipe. Quite common, but many of them are unseen because they likes some concealment by vegetation. (Thet comes out in greater numbers near the end of the day.) With Killdeer, the earliest migrant to arrive in spring and the latest to leave in fall.  Also found in ditches and along the edges of sewage lagoons. 
Greater and Lesser Yellowlegs. Early migrants and common from mid-March to mid-May in spring and from July through September in fall. Lessers greatly outnumber Greaters. Both species like most habitats. As spring migration progresses, Greaters thin out, leaving mainly Lessers. It's the reverse in fall. Lessers arrive first in July, followed soon by Greaters.
Am. Golden-plover. Very common in late March, quite uncommon in fall, when most go back by the Atlantic route. Sizeable flocks usually appear in disked fields, smaller numbers along the dry edges of lakes and ponds. Most are in drab "basic" plumage, but by May there is often an occasional individual in full nuptial regalia. 
Least Sandpiper. Very common. Earliest "peep" to arrive. Latest to depart in fall. (The most likely peep, if any is found in winter). Usually likes drier edges of ponds and lakes but sometimes feeds in shallow water. Not deterred by presence of vegetation.
Baird's Sandpiper. Fairly early spring migrant. Fairly common in April. Present, but less common, throughout summer/fall return flight. Very uncommon to rare after May 1st. Likes drier edges of ponds and lakes but sometimes feeds along water's edge or even wades.
Pectoral Sandpiper. With Least Sandpiper, probably the most commonly-seen peep for most of the migration, spring and fall. Likes just about every habitat, including sod farms and puddles in fields. A few can linger into November.
White-rumped Sandpiper. The latest spring migrant to arrive. Uncommon before May 1st. Becomes the most common peep by the second week of May. When the White-rumps appear in numbers, the shore bird migration is pretty well over. Very rare in fall.
Semi-palmated Sandpiper. Very common, spring and fall. Arrives in numbers later than Least, from mid-April on. By May 1, they are probably the most common peep until mid-May, when the White-rumps take over. Likes sandy open areas. Seen less frequently than Leasts and Pectorals because birding focuses on mucky, vegetated drawn-down impoundments and sandy open areas are harder to find. However, more Semis probably come through than any other peep.
Western Sandpiper. Rare in spring. Uncommon in summer. More likely to outnumber  Semis in September. Feeds by wading in shallow sheet water, whereas Semis are more likely to peck objects from a surface.
Dunlin. Uncommon but regular in shallow sheet water and sandy edges. Will sometimes appear in vegetated area, but does not like it. Migration in fall is less obvious, perhaps because birders have focused their attention on other habitats when the Dunlins come through. Flocks of shore birds in October or November are apt to be Dunlins in basic plumage.
Sanderling. Regular in small numbers in May and in summer. Like sand. Look for this species on the edge of an empty swimming beach.
Stilt Sandpiper. Common wading in sheet water, spring and summer. Does not care too much for vegetation.
Long and Short-billed Dowitchers. Both are fairly common, feeding like sewing machines in sheet water or roosting on sand bars. Long-billeds out number Short-billeds, but their abundance varies with seasonal timing. Most April dowitchers are long-billeds. Most May dowitchers are short-billeds, but there is a period of overlap near the end of April. It is somewhat more complicated in fall. The adult short-billeds arrive first, usually in July. By August, both species are present with Long-billed the most common. Then the juveniles of both species come through in September. In October or later, the probability is Long-billed.
Black-bellied Plover. Quite uncommon, but if you get out regularly you should see the species annually. Hangs around drier edges of ponds and evaporating lakes or on exposed sand bars. Can show up any time, spring or fall, but is usually a fairly late migrant (May) in spring.
Semi-palmated Plover. Moderately common, spring and fall. Likes open mud flats.
Piping Plover. Very rare, but goes through spring and fall. Likes dry sandy edges. Sometimes seen on sandy beaches. You won't see this one every year unless you get out a lot.
Snowy Plover. Even more rare than Piping. Casual except in NW part of state, where very rare. If you find one, it's serendipity.
Avocet. Most common in fall, but occasional in spring, this conspicuous bird strays regularly into our state. Often shows up in flocks. You really cannot go out looking for an Avocet, but I usually see one or more of them at an unpredictable location each year. They are more likely to show up on a lake surrounded by rip rap than most other shore birds. I have seen them swimming in the middle of a lake. I have also seen them in winter just over the state line in Kansas.
Willet. This large shorebird usually shows up during the last half of April or first week of May wading in sheet water. Does not like vegetation. Also found in July and August. Check out sewage lagoons with shallow water for this one.
Hudsonian Godwit. regular spring migrant, usually in April. Extremely rare in fall. Likes sheet water and sand bars. Does not like vegetation.
Marbled Godwit. Rare migrant. Most often found in July, but does occur in spring. Like sheet water or sand bars. Does not like vegetation.
Spotted Sandpiper. Very common, spring and summer. Teeters along edges of lakes and ponds, often when there is no mudflat or sheet water. Teeters on rip rap, exposed logs, even on road. Hard to miss.
Solitary Sandpiper. Common spring and fall. One of the earliest shore birds to arrive in July. Likes small puddles, ditches even streams. As its name suggests, is not seen in flocks. Does not mind vegetation too much.
Ruddy Turnstone. Believed to be rare stray, but may be a bit more common than supposed because it usually comes through late with the White-rumps when most birders have turned their attention elsewhere. Likes open areas. Found along shores. Occasionally found in fall.
Wilson's Phalarope. Common spring and fall. Frequents edges or swims in water.
Red-necked Phalarope. Regular, but uncommon, migrant. Usually seen around the height of the spring migration during the first week in May or in September. To be looked for in sewage lagoons, especially in fall.
Red Phalarope. I have yet to see it in Missouri, have seen it in Kansas twice in spring and once in fall. Best chance for this casual species is probably to look on a lake in very late September or early October.
Long-billed Curlew. Believed to be casual, but I'm not sure. In Kansas, the time and place to see L-B Curlews is in April in green agricultural fields. I have often wondered if a regular search of agricultural fields in April  in Missouri River bottomlands (which few, if any, birders undertake) might yield this species.
Whimbrel. Very rare, spring and fall. (Mostly spring). A matter of luck.
Red Knot. Very, very rare. Likes sandy edges and sheet water. Sometimes found with dowitchers. Best chance probably in summer.
Buff-breasted Sandpiper. As noted before, best looked for on sod farms in August.
Ruff, Curlew Sandpiper, Mountain Plover, Spotted Redshank, Red-necked/Little Stint, Sharp-tailed Sandpiper. Totally accidental. However, with Doug Willis' persistence and luck, you'll probably see one or more of them if you keep at it.
Eskimo Curlew. Hope springs eternal.
Enough said.
Bob Fisher
Independence, MO
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