Documentation of Least Bittern

Observer Information

Reporter:  Dean E Shoup  PO Box 470033,   Aurora, CO  80047-0033
Other Observers:  Bird found previous day by Jeff Parks. During my observation-Bob Spencer and Sandra, Roger Linfield, Frank Farrell and a few others unnamed.

Species, Date, Time and Location Information

Species:  Least Bittern
First Date/Time:  5/19/2016 7:00:00 PM
Last Date/Time:  5/19/2016 8:00:00 PM
Duration (total time in view):  1 hour
County:  Boulder
Specific Location:  Walden Ponds/Sawhill Ponds Complex
Number:  1
Age:  Unknown
Sex:  Male
Plumage:  Breeding


Cattail Marsh

Viewing Conditions

Optics:  Nikon Monarch 7 8x42 and Vortex Diamonback 20x60 Scope
Distance:  20-30 yards
Light:  Clear to Partly Cloudy

Description of the Bird

First thing I noticed was the long white stripe going down a dark colored body.  The bird was being still and all I could see was the long white stripe and dark coloring.  I retrieved my scope and put it on the bird. I then observed the long wedge shaped bill. Dark eye with light ring. The face was light to buff and had a dark cap.  The bird moved around and at one point extended it's long neck, showing a rich rufous orange coloring.  Through the hour I observed the bird it only moved around a little bit, but did jump from one spot to another a few times.  It stretched and looked around, even right toward the group of people observing it. Upon reviewing the photos some streaking on the sides of the breast were present.  I believe this to be a Male based on the darkness of the back feathers matching the head. I am struggling to determine whether this is an Adult Male or First Year Male, the darkness of the back looks to be Adult but I am unsure so I left the Age Unknown.  I ruled out Adult female based on the darkness of the head and back feathers matching. Female would have a darker head contrasting with more of a dark brown back. Immature would be much lighter brown overall according to the Sibley illustrations.  My hunch is that it is a first year male based on the feather appearance but could just be a worn Adult.  The bird was silent and did not make any sounds while I was observing. 

Similar Species Discussion

I did consider Green Heron but felt the long white stripes or bracing plus the buffy face and sides ruled that out. 

Resources Used

Sibley West Second Edition was consulted as well as the full Sibley Second Edition, second printing.  Also  the website of Cornell was also used to look at photographs. 

Previous Experience

I have seen one Least Bittern fly out of a marsh at the Salton Sea.  I have seen 6-7 American Bitterns in Alamosa CO and heard them at Thurston Reservoir.   I have seen around a dozen or so different Green Herons both perched and in flight. 


Notes made DURING observation

Materials Available

Photographer: Dean Shoup

Photos |


Date Documentation Submitted

5/20/2016 11:27:00 PM
Click left or right edges of photos to move through all; click outside image to close

Location Map

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