Beached Bird Guide for Northern Lake Michigan
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Beached Bird Guide for Northern Lake Michigan Prepared by Common Coast Research & Conservation In association with the Grand Traverse Bay Botulism Network © 2008 Common Coast Research & Conservation How to use this guide This guide was developed to aid with the field identification of the most common waterbird species implicated in botulism E die-offs on northern Lake Michigan. The guide is not intended to be a comprehensive treatment of all species you may encounter in the field. For birds not treated in this guide please document with photographs and/or submit carcasses to the nearest Michigan Department of Natural Resources Field Office for identification and/or testing for botulism (see manual). The emphasis of this guide is on differences in bill structure among the various waterbird species. The bill plates are drawn to actual size - we recommend laminating the guide for use in the field. Placing the bills of unknown species directly on the plates will facilitate identification. Please keep in mind some variation among individuals is to be expected. Photographs of unknown species are helpful for later identification. Bird Topography tarsus crown bill (upper and lower mandibles) foot bill margin cheek throat wing coverts (lesser) secondaries webbed foot lobed foot primaries (loons, ducks, gulls) (grebes) Loons and Grebes Birds with dagger-like bills Description: Adult Common Loon bill large, dagger-like, mandible edges smooth feet webbed tarsus narrow, flat Plumage variation (adult vs. juvenile): Look at wing coverts: Adult – well-defined white "windows" (see photo) Juvenile - lacks defined white "windows" Similar species: Red-throated Loon – bill smaller (rarely found) Red-necked Grebe – feet lobed, bill smaller Description: Red-throated Loon bill dagger-like, slightly upturned, mandible edges smooth feet webbed tarsus narrow, flat Similar species: Common Loon - larger; bill heavier, not upturned Red-necked Grebe – feet lobed , bill yellowish NOTE: Rarely encountered. Photograph and collect all individuals Red-necked Grebe Description: bill narrow, yellowish feet lobed Similar species: Common/Red-throated loons – feet webbed Western/Clarke's Grebe (western species) – sharp black and white plumage on head and neck; has not been recorded but is possible (collect if found) Horned Grebe – distinctly smaller, dark bill Description: Horned Grebe small body bill short; depth and width at base equal feet lobed well-defined white cheek patch Similar species: Eared Grebe (western species)– bill deeper than wide at base. Face darker, bill slightly upturned Red-necked Grebe – distinctly larger, bill yellowish Gulls and Cormorants Birds with hooked bills Adult Description: large body Herring Gull bill large, hooked legs pink Plumage variation (by age class): Adult – hooked bill yellow with red spot near tip (usually) Subadult – plumage varies by age; bill uniformly dark in young birds Subadult Similar species: Ring-billed Gull – smaller body and bill; legs yellow in adults NOTE: Non-breeding and subadult Herring Gulls can show dark markings on bill that are easily confused with adult Ring-billed Gulls. Identification should be based on bill structure and size. Adult Ring-billed Gull Description: bill medium-sized, slightly hooked legs yellow (adult) or pink (young of year) Plumage variation (by age class): Adult – bill yellow with dark ring (however, see Herring Gull) Subadult – plumage varies by age; bill usually Subadult bicolored with pink base Similar species: Herring Gull – larger body and bill; legs pink; subadult darker than subadult Ring-billed Gull Adult Double-crested Cormorant Description: bill long, hooked orange facial skin and throat pouch tail distinctly long feet webbed Plumage variation (by age class): Adult – plumage black overall with two white tufts on head (breeding) Subadult – plumage varies but paler and brownish Mergansers and Scoters birds with webbed feet and serrated bills Description: orange bill long & slender with saw-like serrations Common Merganser demarcation between head and neck well-defined (female) Plumage variation: Female-type Breeding male – distinct black/white plumage (see field guide) Female/Juvenile/Non-breeding male – reddish head and neck, white throat Similar species: Red-breasted Merganser – base of upper mandible shallow; less contrast in throat and neck (female) Female-type Description: orange bill long & slender with saw-like serrations demarcation between head and neck poorly defined Red-breasted Merganser (female) Plumage variation: Breeding male – distinct plumage (see field guide) Female/Juvenile/Non-breeding male – reddish- orange head and neck Similar species: Common Merganser – base of upper mandible deeper than Red-breasted; less contrast in throat and neck (female); head more reddish (female) Male White-winged Scoter Description: Bill large with distinct shape, male with knob at base and orange tip Male conspicuous white secondary feathers Bill shows comb-like plates (serrations) Plumage variation: Male – larger knobby bill; velvet black plumage with white “comma” behind eye Female-type Female/Juvenile – brownish plumage with whitish cheek patch Similar species: Other Scoter species (Surf, Black) – lack white secondaries; different bill shape, rarely encountered. Female Common Goldeneye – bill much smaller; feet yellow-orange Ducks birds with webbed feet and bills with comb-like plates Female Description: Common Goldeneye bill dark with yellow tip (female) white secondary feathers webbed feet yellow-orange Male Plumage variation: Female Male – head iridescent black; round white spot in front of eye Female/Juvenile – head brown, lacks white spot Similar species: White-winged Scoter – bill much larger; feet dark Long-tailed Duck – bill smaller; wings all dark Bufflehead – bill smaller; female has brown head with white oval face patch; male has iridescent Male head with white extending around crown Female-type Description: bill small and uniformly dark Bufflehead white patch on secondary feathers Plumage variation: Male –head irridescent; large white patch extends around crown Female Female/Juvenile – head brown with white face patch Similar species: Male Common Goldeneye – bill larger; female lacks white cheek patch; male face patch small and located between eye and bill Male Long-tailed Duck – bill much smaller; lacks white on secondary feathers Male Description: bill small & gray with pink mid-section (in males) Long-tailed Duck wings dark contrasting dark and light plumage distinct Plumage variation: Male – long tail streamers; breast black Female-type Female/Juvenile – short tail Similar species: Common Goldeneye – bill larger; wing larger with white secondary patch Bufflehead – bill similar; head pattern distinct .