Birds in Aquatic Ecosystems Why Birds Important predators

Birds in Aquatic Ecosystems

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: University of Michigan Animal Diversity Web – 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

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 University of Michigan Animal Diversity Web • • • 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

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: University of Michigan Animal Diversity Web – 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

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 sparrowsized to length of a small hawk – Many have very long legs/bills for wading and deep probing of the substrate for invertebrates

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