Documentation of Caspian Tern

Observer Information

Reporter:  Chris MacDonald  49 Fawn Lake Rd,   Durango, CO  81301
Other Observers:  Emily MacDonald, Ryan Votta, Micah Helton, Daniel Helton

Species, Date, Time and Location Information

Species:  Caspian Tern
First Date/Time:  4/11/2022 6:25:00 PM
Last Date/Time:  4/11/2022 7:05:00 PM
Duration (total time in view):  40 minutes
County:  La Plata
Specific Location:  Pastorius State Wildlife Area
Number:  1
Age:  Adult
Sex:  Unknown
Plumage:  Breeding


Mud bank/shore.

Viewing Conditions

Optics:  Swarovski EL 8.5x42 binoculars, Kowa TSN-883 scope with 25-60x zoom
Distance:  50-75 yards
Light:  Cloudy but clear. No rain. Cloud cover provided even lighting with no harsh light or backlighting.

Description of the Bird

First seen by Ryan Votta, Micah Helton, and Daniel Helton late afternoon on 04/11/2022 at Pastorius.  I received a text from Ryan saying that the bird was present.

Single bird about the size of Ring-billed Gull.  Stout red bill with darker tip.  Dark colored legs.  Crown had black cap that extended down to below the eye so the eye of the bird blends in with the black crown cap.  Dark cap color did not extend down the back of lower portion of the head or neck.  Dark forehead.  White face (below eye), neck, breast, belly, and tail.  Light grey back and sides/wings.  Black undersides of primaries could be seen projecting to roughly the end of the tail when the bird was standing with wings folded.  In flight the black undersides of the wing tips were clearly visible.  In flight wings are thin and angular.

Photos of bird are included.

Similar Species Discussion

Eliminated Common Tern because of size and coloration of body, legs, and bill.  

Eliminated Foster's Tern because of size and coloration of body, legs, and bill.

Eliminated gulls because of black cap on head and color of bill.

Resources Used

Prior to heading out reviewed characteristics of the bird using Sibley's field guide and Cornell's "Birds of the World" online bird database.

In the field double checked characteristics using Sibley's field guide and discussed characteristics with four other birders that were present. 

Previous Experience

This is our first experience with this bird.


Notes made DURING observation

Materials Available

Photographer: Chris MacDonald

Photos |


Date Documentation Submitted

4/16/2022 10:30:00 AM
Click left or right edges of photos to move through all; click outside image to close

Location Map

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