Illinois Natural History Survey - University of Illinois

Western grebe
Aechmophorus occidentalis

 

Taxonomy
Occurence in Illinois
Status
Habitat associations
Guilds
Food-habits
Environmental associations
Life history
Management practices
References


TAXONOMY

 

  • Phylum: Chordata
  • Class: Aves
  • Order:
  • Family:
  • Genus: Aechmophorus
  • Species: Aechmophorus occidentalis
  • Authority: Lawrence

Comments on taxonomy:
Originally described in genus Podiceps *09*. Common names include: western grebe (official), swan-necked grebe, or swan grebe *06*.

 


OCCURENCE IN ILLINOIS

A rare migrant but in recent years has been sited fairly consistently during the fall migration *01,04,05*.

 


STATUS

Items in bold indicate applicable categories
Forest Service Categories: S = recommended for regional sensitive status, F = forest listed species, M = management indicator species

Federal Status:

Endangered Threatened Proposed for listing
Candidate for proposal Recovery plan approved Recovery plan received (USFWS)
Recovery plan in preparation Under notice of review Delisted
Migratory EPA indicator Forest Serv.- Shawnee species

State Status:

Endangered Threatened Proposed

Other:

Game Furbearer Nongame protected
Sportfish Commercial Pest None of the above

Comments on status:
Bohlen lists western grebe as a rare migrant in Illinois *01*.

 


HABITAT ASSOCIATIONS

Items in bold indicate applicable categories

General habitat:

Unknown Terrestrial Aquatic Riparian

USFS timber inventory forest size class:

Unknown Unstocked Seedling Sapling
Seedling/sapling Pole Mature Over mature

Land use and land cover:

Unknown   Urban Residential
Commercial
Industrial
Transportation, communication
Complex industrial/commercial
Mixed
Other
Agricultural Crop, pasture
Orchards, groves, nurseries
Feedlot
Other
Rangeland Herbaceous
Shrub and brush
Mixed
Forestland Deciduous
Evergreen
Mixed
Water Stream
Lake
Reservoir
Bay
Wetland Forest
Non-forest
Barren Salt flat
Beach
Sand
Rock
Mine
Transit
Mix

Forest cover types: No records.

Associated tree species: No records.

 

National wetland inventory classifications:

SystemSubsystemClassSubclassWater regime modifiersWater chemistry
Lacustrine Littoral Emergent vegetation Persistent Permanent nontidal Freshwater
Lacustrine Littoral Open water of unknown bottom type   Permanent nontidal Freshwater
Palustrine   Emergent vegetation Persistent Intermittently exposed/permanent nontidal Freshwater
Palustrine   Open water of unknown bottom type   Intermittently exposed/permanent nontidal Freshwater

 

Comments on species-habitat associations:
Western grebe is associated with freshwater lakes and marshes in areas of open water and adjacent rushes and cattails *06,07,08*.

Important plant and animal association: No comments.

High value habitats

HabitatStructural stageSeason
Wetland Not applicable
(HVAL-HAB cover)
All
Marsh Not applicable
(HVAL-HAB cover)
All
Lakes and ponds Not applicable
(HVAL-HAB cover)
All

Species-habitat interrelations: No comments.

 


GUILDS

Feed-guilding:

HabitatStructural stageSeasonFeed-guilds
Wetland Not applicable
(HVAL-HAB cover)
All Water column- arthropods
Water column- invertebrates other than zooplankton or arthropods
Water column- fish
Water surface- arthropods
Water surface- invertebrates other than zooplankton or arthropods
Water surface- fish
Lakes and ponds Not applicable
(HVAL-HAB cover)
All Water column- arthropods
Water column- invertebrates other than zooplankton or arthropods
Water column- fish
Water surface- arthropods
Water surface- invertebrates other than zooplankton or arthropods
Water surface- fish

Comments on feed-guilding:
Adults eat primarily fish *06,07*.

Breed-guilding:

HabitatStructural stageSeasonBreed-Guilds
Wetland Not applicable
(HVAL-HAB cover)
All Marine/estuarine-open water
Lakes and ponds Not applicable
(HVAL-HAB cover)
All Marine/estuarine-open water

Comments on breed-guilding:
Engage in elaborate courtship display in open water *06,07,08*.


FOOD-HABITS

Trophic level is CARNIVORE

Food itemLife stage/plant part
Mollusca Unknown
Crustaceans Unknown
Insecta Unknown
Ephemeroptera (mayflies) Unknown
Hemiptera Unknown
Coleoptera (beetles) Unknown
Diptera (flies, midges, mosquitoes) Larva
Osteichthyes (bony fishes) Juvenile
Osteichthyes (bony fishes) Adult
Clupeiformes (herrings) Unknown
Cypriniformes (carps, minnow, loaches) Unknown
Siluriformes (catfishes) Unknown
Perciformes (basses, sunfishes, perches, sculpins) Unknown
Caudata (salamanders,newts,mudpuppies,sirens,hellbenders) Unknown
Plants & animals not included on list See comments
Important:
Osteichthyes (bony fishes) Juvenile
Osteichthyes (bony fishes) Adult
Juvenile:
Plants & animals not included on list See comments
Adult:
Mollusca Unknown
Crustaceans Unknown
Insecta Unknown
Ephemeroptera (mayflies) Unknown
Hemiptera Unknown
Coleoptera (beetles) Unknown
Diptera (flies, midges, mosquitoes) Larva
Osteichthyes (bony fishes) Juvenile
Osteichthyes (bony fishes) Adult
Clupeiformes (herrings) Unknown
Cypriniformes (carps, minnow, loaches) Unknown
Siluriformes (catfishes) Unknown
Perciformes (basses, sunfishes, perches, sculpins) Unknown
Caudata (salamanders,newts,mudpuppies,sirens,hellbenders) Unknown

Comments on food habits: 
General: Eat a variety of aquatic organisms with a predominance of fish *06, 07*.
Juvenile: Young apparently feed with parents until independent. Initially (as early as 3 days old) may eat large quantities of feathers (238 and 331 have been recorded) *07*.
Adult: Eat a variety of aquatic organisms (insects, crayfish, mollusks, etc.) with a predominance of fish *06,07*.


ENVIRONMENTAL ASSOCIATIONS

General:

  • Air temperature:see comments
  • Water temperature: cool- between 15-30 c
  • Water temperature: cold- between 0-15 c
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Limiting:

  • Air temperature:see comments
  • Water temperature: cool- between 15-30 c
  • Water temperature: cold- between 0-15 c
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Egg

  • Air temperature:see comments
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Feeding juvenile:

  • Water temperature: cool- between 15-30 c
  • Water temperature: cold- between 0-15 c
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Resting juvenile:

  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Feeding adult:

  • Water temperature: cool- between 15-30 c
  • Water temperature: cold- between 0-15 c
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Resting adult:

  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Breeding adult:

  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Water level: permanent
  • Water level: semipermanently flooded
  • Water level: seasonally flooded
  • Water depth preference: 1-5 ft.
  • Water depth preference: 5-10 ft.
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: prairie potholes
  • Aquatic habitats: lake weedbeds
  • Aquatic habitats: marsh

Comments on environmental associations:
General: Associated with lakes and marshes in both open water and emergent vegetation *06,07,08*. Air temperature- eggs must be incubated by parents *06*.
Egg: Nest is built in emergent vegetation over water up to 10 ft. deep. May be up to 15 in. above the water. Nest is constructed of Scirpus (bulrush) and other aquatic vegetation *06*. Eggs must be kept warm and are incubated by both sexes *06*.
Feeding juvenile: Juveniles feed in shallows among emergent vegetation with adults *06,07,08*.
Resting juvenile: Juveniles rest in emergent vegetation in lakes & marshes with adults when not feeding *06,08*.
Feeding adult: Adults feed in shallows among emergent vegetation and in open water *06,07,08*.
Resting adult: Rest in emergent vegetation in lakes and marshes *06,08*.
Breeding adult: Breed in inland lakes and marshes *06,08*.


LIFE HISTORY

Origin: Rare migrant *01*.

Physical description: Adult - head crown and nape black, rest of head and neck white, iris of eye scarlet *06*; neck is long, bill is long and needlelike *07*; rest of body is black-gray *06,07*. Sexes are similar in appearance *06,07*. Size - 22-29 in. long, wingspan 30-40 in., weight up to 4 lb. *06,07*. Young - plain grey plumage, not striped as in other grebe species *06,08*.

Reproduction: Breeding season - April-May *07*; incubation period - about 23 days *08*; 3-4 eggs are laid/female, dump nesting may result in as many as 16 eggs in one nest, eggs are laid mid May-June *07*; sexually mature at one year but age of first breeding is unknown *06*.

Behavior: Territoriality - nests are closely spaced and area defended is only the immediate vicinity of nest *06*. Migration - leave breeding grounds in late summer, migration primarily from east to west *07*. It is during this period that western grebes have been most commonly sited in Illinois *01,04,05*. Dispersion - are colonial during breeding season *07*; foraging strategy - dive for aquatic organisms (fish, insects, crayfish, etc.) *07*. Nest in emergent vegetation of lakes & marshes *06,07,08*. Parental care of young - incubation and defense of eggs is by both sexes, young crawl on parents' back and are thus initially transported both over and under water *06,07,08*. Development of young - can swim and dive soon after hatching *08*; age when first fly and of independence is unknown *06,07*.

Limiting factors: Wetland habitat is the primary limitation *07*.

Population parameters: Relative trend - unknown but may be declining due to loss of wetland habitat *00*.

 


MANAGEMENT PRACTICES

Beneficial:

  • Controlling pollution in aquatic habitats
  • Controlling water levels
  • Developing/maintaining lakes and ponds
  • Creating/maintaining islands within permanent impoundments
  • Developing/maintaining wetlands
  • Creating/maintaining wetlands from non-wetlands
  • Protecting existing wetlands
  • Prohibiting hunting
  • Developing/maintaining greenspace (wildlife corridors)
  • Creating impoundments
  • Developing islands for waterfowl

Adverse:

  • Controlling aquatic plants
  • Draining wetlands

Existing:

  • Prohibiting hunting

Comments on management practices:
There are no existing management practices in Illinois specifically for the western grebe due to its uncommon occurrence. Protection of wetland habitat would be beneficial.

 


REFERENCES

0. SANDBERG, S. 1985. ILL. NAT. HIST. SURV., 607 E. PEABODY DR., CHAMPAIGN, IL. 61820. (217)333-6846.

1. BOHLEN, H.D. 1978. AN ANNOTATED CHECK-LIST OF THE BIRDS OF ILLINOIS. ILLINOIS STATE MUS. POP. SCI. SER. VOL. IX. 156 PP.

2. U.S. FISH WILDLIFE SERVICE, 1983. CODE OF FEDERAL REGULATIONS. TITLE 50, WILDLIFE AND FISHERIES, CHAPTER 1, PP. 11-18, 50 CFR 10.13. LIST OF MIGRATORY BIRDS. SPECIAL PUBL. FEDERAL REGISTER, GENERAL SERVICES ADMIN. OCTOBER 1.

3. ILLINOIS DEPARTMENT OF CONSERVATION. 1980. CONSERVATION LAWS. CH. 61. WILDLIFE, ART. II, PAR. 2.2. REPRINTED FROM ILLINOIS REVISED STATUTES, 1979. WEST PUBL. CO., ST. PAUL, MN. 120 P.

4. KLEEN, V.M. 1983. FIELD NOTES, 1982. FALL MIGRATION. ILLINOIS AUDUBON BULL. 204:45-56.

5. KLEEN, V.M. 1984. FIELD NOTES, 1983. FALL MIGRATION. ILLINOIS AUDUBON BULL. 208:30-46.

6. PALMER, R.S. 1962. HANDBOOK OF NORTH AMERICAN BIRDS. VOL. 1. YALE UNIV. PRESS, NEW HAVEN, CONNECTICUT. 567 PP.

7. TERRES, J.K. 1980. THE AUDUBON SOCIETY ENCYCLOPEDIA OF NORTH AMERICAN BIRDS. ALFRED A. KNOPF. NEW YORK. 1109 PP.

8. BENT, A.C. 1919. LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. U.S. NATL. MUS. BULL. 107:1-245.

9. LAWRENCE. 1858. PODICEPS OCCIDENTALIS LAWRENCE. IN: BAIRD, COSSIN, & LAWRENCE, REP. EXPLOR. SURV. R.R. POC. 9. PP. 892, 894.

 


 

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