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Coordinators: 1cy June 2cy Jan 3cy Jan adult Jan |
adult: MarchBelow you will find a description of Chapter 16 HEERMANN'S GULL Larus heermanni, as published in one of the best Gull publication: "Gulls of the Americas" by Steve Howell & Jon Dunn. "we" in the text below refers to the original authors. If any errors occur in this text, please let me know and mail to marsmuusseatgmaildotcom. PART I: STATUS AND DISTRIBUTION DESCRIPTION AND MOLTAdult Cycle. Complete PB molt (May/mid-June-Sept./Oct.) produces adult basic plumage: head, neck, and underparts gray, head speckled and mottled dark slaty to brownish with whitish-grizzled forehead and lores, white eye-crescents, and whitish throat. Upperparts darker, slaty gray (Kodak 10-11-5) with bold whitish scapular crescent, broad whitish tertial tips, and pale gray uppertail coverts. Flight feathers blackish, tail boldly tipped pale gray to white, secondaries and inner primaries boldly tipped white, with narrower whitish tips out to about P7. Some adults (< 1 percent) have a variable number of white primary coverts forming a bold white patch on the upperwing. Underwings dark. Eyes brown to pale grayish with narrow gray to reddish orbital ring, legs blackish. Bill red to bright red with black distal third and small whitish to pale reddish tip, sometimes a small greenish area at mandible base during height of molt. Partial PA molt (Sept./Oct.-Jan./Feb.) produces adult alternate plumage: head becomes clean bright white, orbital ring bright red, bill brighter overall and averages reduced distal black. In years of reduced breeding effort (due to food shortages), some birds may attain variable dusky gray mottling on head in alternate plumage. Slaty plumage often bleaches to brownish by summer, so birds undergoing PB molt show a mixture of clean slaty gray and faded brown feathers.
First Cycle. Juvenile (July-Sept.): dark sooty brown overall, slightly paler on underparts, with smoky gray throat. Upperparts with scaly buff edgings - varying individually from very broad to fairly narrow; subscapular and tertial tips can bleach to form pale crescents. Flight feathers blackish, secondaries, inner primaries, and tail narrowly tipped buffy white, which often wears away. IN FLIGHT: dark brown overall with blackish flight feathers, bleached upperwing coverts sometimes forming a paler mid-wing panel; underwings dark. Eyes dark, legs blackish. Bill blackish with dull flesh base, becoming dull flesh pink with black tip. Variable PA1 molt (Sept.-Mar.) often includes upperwing coverts and, in tropical populations, can include primaries.(5) First alternate plumage: head, neck, chest, and flanks dark sooty brown, often mixed with faded juvenal feathers; eye-crescents brown to pale gray and throat whitish; some birds attain whitish flecks in face. Back and variable number of upperwing coverts and tertials dark sooty gray-brown, new subscapulars and tertials tipped pale gray. Retained juvenal wing coverts often bleach to a contrasting pale panel. Bill flesh pink with black tip, often some gray-green basally.
Second Cycle. Complete PB2 molt (Apr.-Aug.) produces second basic plumage: dark sooty brown to gray-brown overall, often with head and neck darker sooty brown; throat smoky gray, eye-crescents brownish to pale gray. Subscapulars and tertials broadly tipped whitish, uppertail coverts mottled smoky gray. Flight feathers blackish; secondaries, inner primaries, and tail narrowly tipped whitish (often lost by wear). Eyes dark brown with narrow gray orbital ring, legs blackish. Bill pinkish orange with gray-green to bluish green base and black distal third with fine pale tip. Partial PA2 molt (Aug.-Mar.; usually includes some upperwing coverts, often some tertials, sometimes inner rectrices) produces second alternate plumage: grayer overall than second basic. Head varies from dark sooty brown with whitish throat and eye-crescents to variably mottled whitish (some may attain mostly white head, perhaps especially in good food years). Some birds attain boldly white-tipped inner rectrices, most often R1. Bill often brightens in spring to orange-red with black distal third and fine pale tip, some still with blue-gray base; most-retarded birds have pinkish bill with black tip, similar to first alternate; orbital ring reddish to bright red.
Third Cycle. Complete PB3 molt (May-Sept.) produces third basic plumage: variably intermediate between B2 and adult basic. Retarded birds dark sooty overall with dark sooty hood variably grizzled whitish in face and on crown, pale gray to whitish eye-crescents. Advanced birds brownish gray overall, darker above, with head coarsely mottled dark brown, throat whitish, face grizzled white and with white eye-crescents. Scapular crescent white and tertials broadly tipped pale gray to white. Flight feathers brownish black, tail boldly tipped pale gray to white, secondaries boldly tipped white, with narrower white tips out to about P5. Eyes brown to pale brown with narrow gray to greenish orbital ring, legs blackish. Bill reddish orange to red with greenish base, black distal third tipped ivory. Partial PA3 molt (Sept.-Feb./Mar.) into third alternate plumage: overall grayer and adultlike, head clean white or with variable dark mottling. Some probably indistinguishable from alternate adult: note flight feathers average browner with narrower white tips to tail and secondaries. Orbital ring becomes red, bill bright red with black distal third and pale tip. Adult plumage attained by complete PB4 molt (May/June-Sept./Oct.).
HYBRIDS NOTES |
 Heermann's Gull heermannii adult, March 19 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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 Heermann's Gull heermannii adult, March 19 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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 Heermann's Gull heermannii adult, March 19 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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 Heermann's Gull heermannii adult, March 19 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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 Heermann's Gull heermannii adult, March 19 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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 Heermann's Gull heermannii adult, March 05 2017, Pismo Beach, California USA. Picture: Alex Abela. |
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Heermann's Gull heermannii
