Birds and Mammals in Aquatic Ecosystems ENV 311/ EEB 320 Winter 2007

Why Birds? Important predators of invertebrates, fish, mammals, reptiles and amphibians in aquatic ecosystems Major vectors for transport of plants and wingless invertebrates Interesting and ubiquitous members of aquatic communities Along with fish, enjoy fairly broad support from the public –Good way to generate interest in habitat preservation/restoration

Family Gaviidae Gavia Loons Habitat: mainly northern lakes Notes: –Divers: feed mainly on fish –Very distinctive vocalizations Alarm call Short hoot –1 breeding sp. in MI: common loon (Gavia immer) University of Michigan Animal Diversity Web

Family Ardeidae Bitterns, Herons, and Egrets Habitat: Open wetlands, lakeshores, rivers Notes: –Often seen stalking prey: feed mainly on fish, also amphibians and invertebrates –Egrets/herons often build nests in shrubs/trees and may be colonial breeders –Bitterns prefer dense emergent vegetation and tend to be solitary University of Michigan Animal Diversity Web

Family Ardeidae Bitterns 2 spp. in Michigan American bittern: –Call distinctive—like a piledriver in a puddle? –Secretive, often strikes vertical pose to blend in with vegetation

Family Ardeidae Herons and Egrets 6 spp regularly found in MI Less secretive and more easily spotted than bitterns Egrets are white, herons may be various colors University of Michigan Animal Diversity Web

Family Accipitridae Hawks and eagles 2 spp. that are most often found in MI aquatic ecosystems are: –Bald eagle (above) –Northern harrier (below) Bald eagle found along rivers/wetlands, often preys on fish –Making strong recovery from very low numbers for last half of 20 th century Northern harrier often hovers over open wetlands, preys on small mammals, amphibians and other birds University of Michigan Animal Diversity Web

Family Pandionidae Pandion haliaetus Osprey (1 sp.) Habitat: Mainly rivers and wooded edges of lakes Notes: –Build enormous nests of sticks high off the ground, 3-5 ft in diameter –Feed mainly on fish but cannot swim—have been known to drown if they hook into too large a fish –As with many raptors, numbers have risen since elimination of DDT from the food web University of Michigan Animal Diversity Web

Family Laridae Gulls and terns Ring-billed gull Common tern Gulls tend to be thicker-billed and stouter; frequently walk –Facultative predator/scavenger Terns are sleeker, designed for capturing fast prey –More predatory on small fish and invertebrates May build nests on rocky shores, islands or floating mats of vegetation University of Michigan Animal Diversity Web

Family Anatidae Ducks, geese and swans Very diverse aquatic family Habitats vary, from wooded wetlands and rivers (wood duck) to open water (greater scaup) Notes: –Many feed by dabbling, i.e., sifting through mud for nutritious invertebrates, seeds, shoots, etc. –Others are active predators of fish (e.g. mergansers) –Many valued by hunters— benefit (?) from conservation efforts –Webbed feet for swimming University of Michigan Animal Diversity Web

Family Anatidae Ducks Short-necked, often with colored primary feathers –Most species migratory –Most have sexually dimorphic coloration Mallard (Anas platyrhyncos) very common and spreading in NA Am. black duck (Anas rubipres) very closely related to mallard and disappearing due to interbreeding

Family Anatidae Geese and Swans Longer-necked and usually larger than ducks Mainly migratory--most prefer more northerly breeding ranges than ducks Canada goose (Branta canadensis) is very common near water/grass in MI

Family Gruidae Grus canadensis Sandhill crane Habitat: migratory; wetlands critical for breeding success; past population declines mirrored wetland loss Notes: –Omnivorous, but notorious for eating waterfowl eggs during breeding season –Elaborate mating dance –Social, gregarious bird

Family Alcedinidae Ceryle alcyon Belted kingfisher Habitat: waterways and lakes with available perches and abundant food Notes: –Nest in 1-2 meter long tunnels, often in riverbanks –Voracious predator of small fish –Call is rattling

Family Charadriidae Sandpipers and phalaropes Habitat: shores of lakes, wetlands, large rivers Notes: –Speciose group (18 spp. commonly migrate through or reside in MI) –Size ranges from sparrow- sized to length of a small hawk –Many have very long legs/bills for wading and deep probing of the substrate for invertebrates

Mammals Although most mammals will periodically visit aquatic ecosystems, only a few species are strongly associated with water in MI –Some are voracious predators of fish and mollusks –Others may construct large structures and significantly alter hydraulics of flowing waters –All have physiological adaptations, such as webbed feet and waterproof fur that allow them to thrive in aquatic ecosystems

Castor canadensis American beaver Notes: –Noted for its ability to construct wood/earth dams, altering flow to suit its needs –Uses large, gnawing teeth to fell trees Consumes nutritious bark/buds Uses wood for dam- building –Characterized by large size (may reach 35 kg) waterproof coat and large, paddle-like tail –Trapped to near dangerous levels in 19 th century; now common in most of NA

Lutra canadensis River otter Notes: –Intelligent and very adaptable predator—one of the few natural predators of snapping turtles –Prefers deep, relatively isolated rivers with healthy fish populations –Highly adapted for speed in water: sleek, with fully webbed feet

Mustela vison Mink Notes: –Well-adapted for hunting on land and in water— can swim well and run fast –Feeds on small mammals, fish, amphibians, birds –As with other aquatic animals, may take up residence in old muskrat or beaver lodges

Ondatra zibethicus Muskrat Notes: –Looks most like a small beaver, but can be distinguished by its thick rat-like tail –Builds easily recognizable lodges in shallow wetlands –Mainly herbivorous but will take crustaceans and mollusks as well

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