Birds and Mammals in Aquatic Ecosystems

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

2. 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

3. Family GaviidaeGavia • 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

4. 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

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

6. Family ArdeidaeHerons 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

7. Family Accipitridae University of Michigan Animal Diversity Web • 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 20th century • Northern harrier often hovers over open wetlands, preys on small mammals, amphibians and other birds

8. Family PandionidaePandion 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

9. 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

10. 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

11. Family AnatidaeDucks • 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

12. Family AnatidaeGeese 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

13. Family GruidaeGrus 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

14. Family AlcedinidaeCeryle 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

15. 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

16. 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

17. 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 19th century; now common in most of NA

18. 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

19. 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

20. 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

21. The End