Decline in Birdlife Occurs With Changes in Management of Saline Wetland

By James Ed. Ducey

A change in management goals has meant a decline in the number of bird species present at the Frank Shoemaker Marsh, a saline wetland north of Lincoln.

The comparison of bird records from a 32-year period indicates there are now fewer species of waterfowl, grebes, and - to a lesser extent - egrets and night-herons.

Aerial view of Federation Marsh showing historic extent of open water habitat in southern basins.

Historically, the 160-acre tract once known as Federation Marsh, was managed primarily for the benefit of waterfowl hunting. An electric pump operated by landowner, the Wildlife Development Federation of North America, was used to take water from Little Salt Creek and place it into three wetland basins. The higher water levels were attractive to waterfowl and other waterbirds.

Without the augmentation of water levels at Shoemaker Marsh, and due to control structures put in place by the renovation project completed in the spring of 2007, water depths are maintained at a lower level.

The present focus for habitat management at Frank Shoemaker Marsh is to create saline places that may potentially be useful for the endangered Salt Creek Tiger Beetle, according to Lincoln Parks and Recreation officials, the current land owners.

Especially evident is a lesser number of waterfowl species, in comparison to the 1980s marsh setting. Ducks not recorded in recent years are members of these food foraging guilds: water bottom forager, water diver, water bottom gleaner. Each species would dive in deeper water to feed. Two species of geese have not been recorded either, since being seen in 1985, or 1989.

Foraging guilds are a useful means to group species which have common habits or traits in obtaining food.

Common Name	1975	'77	'78	'79	'80	'81	'82	'83	'84	'85	'86	'87	'89	'94	'95	2001	'03	'04	'07
Greater White-fronted Goose	-	2 *	-	-	1	-	1	-	-	1	-	-	-	-	-	-	-	-	-
Snow Goose	-	1	-	1	1	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Canada Goose	-	3	-	1	1	-	1	1	1	3	1	-	4	1	-	1	2	2	4
Muscovy Duck	-	-	-	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-
Wood Duck	1	-	-	-	2	-	1	-	1	5	-	1	2	-	-	-	-	1	3
Gadwall	5	4	-	5	-	1	2	-	-	2	1	-	-	-	-	-	-	-	-
American Wigeon	5	5	-	11	-	-	-	-	-	1	1	-	-	-	-	-	-	-	1
Mallard	7	7	1	12	11	3	5	-	1	5	-	-	6	-	-	1	-	-	9
Blue-winged Teal	7	3	1	7	18	3	5	1	1	6	-	1	6	1	1	-	-	1	9
Northern Shoveler	7	5	-	13	14	1	2	1	-	4	1	1	5	-	-	-	-	-	4
Northern Pintail	5	10	-	10	5	2	1	-	-	2	-	1	-	-	-	-	-	-	1
Green-winged Teal	6	5	-	6	11	2	1	1	-	3	-	-	2	-	-	1	1	-	4
Canvasback	-	2	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Redhead	8	5	-	3	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Ring-necked Duck	-	1	-	4	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Lesser Scaup	4	3	-	3	7	1	-	-	-	-	1	-	-	-	-	-	-	-	-
Bufflehead	2	1	-	6	1	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Hooded Merganser	-	-	-	-	1	-	-	-	-	-	1	-	-	-	-	-	-	-	-
Common Merganser	1	2	-	2	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1
Ruddy Duck	1	-	-	4	5	-	-	1	1	1	-	-	-	-	-	-	-	-	-
* The value shown is the number of times a species was recorded during the given year, not the number of each species counted.

View to the north, from the southwest corner of Shoemaker Marsh. J.E. Ducey photo. October 23, 2007.

Differences in species diversity is readily shown by the records. The shallow water present at the basins is still a haven for dabbling ducks and the Wilson's Snipe, but has not been useful for diving ducks for several years. It should be noted that the Common Merganser was not present on the wetland basins, but at a bit of open water on Little Salt Creek.

A comparison also shows a difference with grebe species. The lack of the Pied-billed Grebe, a relatively common species at eastern Nebraska wetlands, is especially apparent. No grebes were noted during any of the 15 bird surveys conducted during February to October, 2007.

Grebes belong to the water diver foraging guild, so lower water levels would reduce the deeper water needed for a food source to thrive, and which these birds would dive to obtain.

The Great Blue Heron is usually always present at the marsh area, typically seen quietly stalking along Little Salt Creek, in search of a tasty morsel, or inadvertently flushed from this area by a visitor. It is not known what caused the notable influx of egrets in 1985.

Common Name	1975	1979	1980	1981	1982	1983	1984	1985	1986	1987	1989	2003	2004	2007
Pied-billed Grebe	1	-	-	1	2	-	1	5	1	1	-	-	-	-
Horned Grebe	-	-	1	-	-	-	-	-	-	-	-	-	-	-
Red-necked Grebe	-	-	-	-	-	-	1	-	-	-	-	-	-	-
Eared Grebe	-	-	3	-	1	-	-	1	-	-	-	-	-	-
American Bittern	1	-	4	-	-	-	1	2	-	-	-	-	-	2
Least Bittern	-	-	-	-	1	-	-	3	-	-	-	-	-	-
Great Blue Heron	1	1	1	2	1	1	1	2	-	1	2	2	2	7
Great Egret	-	-	-	-	1	-	-	1	-	-	-	-	-	-
Snowy Egret	-	-	-	-	-	-	-	1	-	-	-	-	-	-
Cattle Egret	-	-	-	-	-	-	-	1	-	-	-	-	-	-
Green Heron	-	-	1	4	4	-	1	1	-	-	-	-	1	-
Black-crowned Night-Heron	-	-	2	-	1	-	-	1	1	-	2	-	-	-

The reason for there not being any egrets or night-herons, may possibly be connected to the lower water levels, which could mean a lack of suitable food resources for these water or marsh habitat species.

Open habitat present following the wetland renovation, was beneficial to one species. The Semipalmated Plover had not been noted since 1989, but several of these birds were present this spring at Shoemaker Marsh, foraging at the bare ground areas.

Arbor Lake WMA, across North 27th Street near Frank Shoemaker Marsh, is also being managed in a manner to maintain lower water levels. There are fewer detailed records for this wetland, but there is some indication that there is also a reduced species diversity, comparing records back to 1977.

An indirect result of increased water levels at these two wetland areas, has meant an increase in the growth of emergent wetland plants, which would result in fewer bird species, especially those which prefer to forage on barren, open mud flats or saline flats.

Wetlands along North 27th Street, north of Arbor Road have been a regular destination for local birders interested in seeing what might happen to be present. The first known record for the area was the Greater White-fronted Goose, seen in 1899, with a few species notes from visits in the latter 1920s and early 1930s. White-faced Ibis have not been noted since 1953. Repeated surveys did not start until 1975 with visits from ornithology students. Plovers - such as the Black-bellied Plover or American Golden-Plover - have not been noted since 1979. Numerous surveys were conducted during the early 1980s. There have not been any Forster's Terns since a 1989 survey.

The overall tally of species for this area of wetlands, with limited prairie and woods, is 199 species. There have been 153 bird species seen at Shoemaker Marsh, with 89 recorded during 2007, through October.

View of southeast wetland basin at Shoemaker Marsh. J.E. Ducey photo, October 23, 2007

The number of species recorded during a particular year, is dependent on the number of surveys, and surveyors. A greater number of visits typically results in a larger tally of species. Since the level of skill varies among bird watchers, having different people observing can result in a larger variety of species being seen.