IBA Site Information

Lake Rathbun Reservoir

State IBA

Appanoose County

Directions: From the north turn right/west off Highway 5 at Moravia for about 2mi then turn left/south on J5T for 5mi to the dam. From the south turn off on J29 to Rathbun continue through Rathbun for about 2mi to the Dam.

Description: Rathbun is significant to several of the endangered and threaten species listed in Category 1. 1)Bald Eagles Nest, Pass through and winter here. It seems to me Bald Eagle should be remove from this list it is definitely no longer endangered or even threaten. 2)Northern Harrier has nested, probably nests most years. Harriers are recorded on CBC at relative high numbers for this latitude around 15+/year most years and it over winters in small numbers every year. 3) Least Tern has summered one time in the last twenty years. Shorteared Owl Occasionally winters in large numbers 20+ almost always can be found in winter. Long-eared Owl winters in large numbers 4 to 18 in 2 to 3 groves that are found each year. More are suspected tobe present but all the many pine groves are not checked. Category 2 / Birds that nest at Lake Rathbun from this category are: 1) Am Woodcock uncommon 2)Pileated Woodpecker one or two pairs 3) Bell's Vireo uncommon but regular 4) Wood Thrush Common 5) Prothonotary Warbler Rare upper end of Lake. 6) Grasshopper Sparrow common. 7) Bobolink Common. Category 3 / The most siginicant habitants are the large number of pine groves which surround the Lake and the reservoir itself. Category 4 / Vertually all species of waterfowl regularly seen in Iowa have been recorded at Lake Rathbun. Major concentrations of Richardsoni Canadas 1 to 2m will winter until total iceup. Mallard numbers can reach 50,000 individual before iceup. Other species that concentrate in high number for Iowa are Common Loon, Horned Grebe, Ring-necked Duck, and Common Merganser. Gulls and Terns - Franklin Gulls in Fall number 20000 for upto several weeks. Caspain Terns and Common Tern are found in hich concentration for Iowa. Shorebird and Waders - Although all the shorebirds and waders on the Iowa list but Least Bittern, Yellow-crowned NightHeron, and Black-necked Stilt have been seen here it is only during high water conditions that high numbers have been recorded. Raptors and Landbirds - The only concentration in this group that might qualify as unusal would be Leconte's sparrows in fall 25+ at times. Single species Concentration that reach 5% of the state population - Franklin gulls 20m+ and Richardsoni Canadas other possiblities that might exceed 5% Mallard 50m, Am White Pelican 3m, Double Crested Cormorant 5m, Common Merganser 10m and Long-eared Owl 20+. Category 5 / Site is heavily birded so long term population study might benefit from the records from this area.

Criteria for this site
Significant species concentrations

Habitats found in this site
Wetland
Savanna/Shrub

Ownership
State
Federal