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Montana Animal Field Guide

Montana Field Guides

Bonaparte's Gull - Chroicocephalus philadelphia

  • Bonaparte`s Gull
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Global Rank: G5
State Rank: SNA

Agency Status
USFWS: none
USFS: none
BLM: none
CFWCS Tier: 4
PIF: none
 

General Description
Sexes similar in all plumages. Breeding plumaged adult has entirely black head with narrow white eye-crescents, gray mantle, white tail, white underparts, black bill, and orange-red legs. Nonbreeding adult similar except head entirely white with characteristic dark ear spot behind eye, and gray hindneck.

General Distribution
Montana Range



Western Hemisphere Range

 


Summary of Observations Submitted for Montana
Number of Observations: 120

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

Breeding
(direct evidence "B")

Breeding
(indirect evidence "b")

No evidence of Breeding
(transient "t")

Overwintering
(regular observations "W")

Overwintering
(at least one obs. "w")


 

(Records associated with a range of dates are excluded from time charts)



Migration
Most of Montana is in the main migration path. Bozeman migration dates are May 4 to 15, with peaks on May 10. Fall records are mostly for November (Skaar 1969).

Habitat
Bonaparte's Gulls prefer larger lakes, but occur on smaller ponds as well (Skaar 1969).

Food Habits
Diet consists of small fish, euphausids, amphipods, and insects.

Reproductive Characteristics
Single brooded species with three eggs per brood. Incubation period twenty-four days.

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Citation for data on this website:
Bonaparte's Gull — Chroicocephalus philadelphia.  Montana Field Guide.  Retrieved on February 9, 2010, from http://FieldGuide.mt.gov/detail_ABNNM03050.aspx
 
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