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Montana Field Guide

Montana Field Guides

Bonaparte's Gull - Chroicocephalus philadelphia

Native Species

Global Rank: G5
State Rank: SNA


Agency Status
USFWS: MBTA
USFS:
BLM:
PIF:


 

External Links





 
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.

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

Species Range
Montana Range Range Descriptions

Migratory

Western Hemisphere Range

 


Observations in Montana Natural Heritage Program Database
Number of Observations: 1268

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

Recency

SUMMER (Feb 16 - Dec 14)
Direct Evidence of Breeding

Indirect Evidence of Breeding

No Evidence of Breeding

WINTER (Dec 15 - Feb 15)
Regularly Observed

Not Regularly Observed


 

(Observations spanning multiple months or years 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).

National Vegetation Classification System Groups Associated with this Species

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.


References
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Citation for data on this website:
Bonaparte's Gull — Chroicocephalus philadelphia.  Montana Field Guide.  .  Retrieved on , from