Criteria for IBA Designation

IBA Criteria Categories

Click headers to read details.

Category 1 - Sites important to endangered or threatened species in Iowa.

This category includes the current list of Threatened or Endangered bird species for Iowa. Three of these species (Bald Eagle, Piping Plover, Least Tern) are also currently on the federal Threatened and Endangered species list. Species must be breeding 2 years of the previous 6 years (since 1999), with evidence of either confirmed or probable breeding according to definitions given in the Iowa Breeding Bird Atlas, figure 4, page 5.

Endangered Species

• King Rail
• Piping Plover
• Least Tern
• Northern Harrier
• Red-shouldered Hawk
• American Barn Owl
• Short-eared Owl
• Peregrine Falcon

Threatened Species

• Long-eared Owl

Category 2 - Sites important to species of high conservation priority in Iowa.

Species selected by the Technical Committee as being of high conservation priority. A site has to support at least three species from this category in order to be nominated. The same three species must be present at the site for 2 or more years out of the previous 6 years (since 1999) with evidence of either confirmed or probable breeding according to definitions given in the Iowa Breeding Bird Atlas, figure 4, page 5.  (See Appendix for habitat assemblages for category 2 species.)

Greater Prairie-Chicken	Black-billed Cuckoo	Chuck-will's-widow
Common Gallinule	American Woodcock	Black Tern
Forster's Tern	Least Bittern	American Bittern
Black-crowned Night Heron	Bald Eagle	Broad-winged Hawk
Pileated Woodpecker	White-eyed Vireo	Bell's Vireo
Loggerhead Shrike	Bewick's Wren	Veery
Wood Thrush	Grasshopper Sparrow	Henslow's Sparrow
Yellow-breasted Chat	Bobolink	Worm-eating Warbler
Kentucky Warbler	Hooded Warbler	Cerulean Warbler

Category 3 - Sites that contain rare or unique habitat within the state or an exceptional representative of a natural habitat, and that hold important species or species assemblages largely restricted to a distinctive habitat type.

Presumably such sites will include some species from the lists in categories 1 and 2, although the site might just be an especially good woodland, grassland, or other area. (One example would be winter roost sites for large numbers of owls.)

Category 4 - A site that regularly holds significant concentrations of one or more species.

A one-time count of qualifying concentrations must occur 2 out of previous 6 years (since 1999).

The following criteria were selected:

• 4a. Waterfowl-a threshold of at least 500 waterfowl in winter or 1,000 in migration. Canada Geese were specifically excluded in these counts.
• 4b. Gulls and Terns-a threshold of at least 1,000 gulls or 100 terns with the following qualifiers: 5,000 for Franklin's Gull, 250 for Black Tern.
• 4c. Shorebirds-a threshold of at least 500 shorebirds.
• 4d. Wading birds-a threshold of at least 25 breeding pairs or 100 feeding or migratory birds.
• 4e. Raptors-a threshold of at least 1,000 total migratory raptors (seasonal total). We also added a category of 100 for wintering birds such as Bald Eagle.
• 4f. Landbirds-No threshold limits were established.
• 4g. Single-species concentrations - a minimum of 5% of statewide population for a species.
  • Common Loon - - Minimum 50
  • Pied-billed Grebe - - Minimum 50
  • American White Pelican - - Minimum 750
  • Double-crested Cormorant - - Minimum 500
  • Bald Eagle (migrants) - - Minimum 75
  • American Coot - - Minimum 2,500

Category 5 - Sites important for long-term research and/or monitoring that contribute substantially to ornithology, bird conservation, and/or education.

We noted that some of the raptor viewing sites (e.g., Hitchcock Area, Grammar Grove) may fit in better in this category than in 4e above.

Appendix - Habitat breakdown for Category 2 species.

The birds listed in Category 2 break down approximately as follows relative to habitat categories:

Wetlands-6 species

• American Bittern
• Least Bittern
• Black-crowned Night-Heron
• Common Moorhen
• Forster's Tern
• Black Tern

Riparian habitats-2 species

• American Woodcock
• Prothonotary Warbler

Woodlands-11 species

• Broad-winged Hawk
• Black-billed Cuckoo
• Chuck-will's-widow
• Pileated Woodpecker
• Bewick's Wren
• Veery
• Wood Thrush
• Cerulean Warbler
• Worm-eating Warbler
• Kentucky Warbler
• Hooded Warbler

Grasslands-3 species

• Greater Prairie-Chicken
• Grasshopper Sparrow
• Bobolink

Savanna/Shrub habitats-4 species

• Loggerhead Shrike
• White-eyed Vireo
• Bell's Vireo
• Yellow-breasted Chat

IBA Criteria Species

Click an image for enlarging or a scroll them all.

Thanks to Jim Dinsmore for the text and to the following photographers for the use of their images: Larry Dau, Jim Durbin, Bruce Ehresman, Jay Gilliam, Bruce Morrison, Kent Nickell, Jim Rathert, Ross Silcock, Dick Stilwell, and Larry Stone.

IBA Summary

131 total IBAs

Species	IBAs Recorded	Total Observations
American Bittern	44	421
Least Bittern	35	333
Black-crowned Night Heron	44	338
Bald Eagle	82	11262
Northern Harrier	69	2637
Red-shouldered Hawk	58	927
Broad-winged Hawk	61	1040
Peregrine Falcon	50	622
Greater Prairie-Chicken	3	288
King Rail	9	45
Common Gallinule	26	321
Piping Plover	22	268
American Woodcock	58	414
Forster's Tern	55	1454
Least Tern	21	207
Black Tern	56	1054
Black-billed Cuckoo	66	500
American Barn Owl	13	54
Long-eared Owl	27	136
Short-eared Owl	37	396
Chuck-will's-widow	5	77
Pileated Woodpecker	62	3369
Loggerhead Shrike	38	210
White-eyed Vireo	33	541
Bell's Vireo	58	1260
Bewick's Wren	4	35
Veery	37	524
Wood Thrush	67	2083
Cerulean Warbler	37	820
Worm-eating Warbler	19	163
Kentucky Warbler	41	680
Hooded Warbler	26	142
Yellow-breasted Chat	44	622
Grasshopper Sparrow	77	1113
Henslow's Sparrow	61	1118
Bobolink	72	1257