Bird Banding at the Allegra Collister Nature Preserve

Important Note about the Allegra Collister Nature Preserve:
It is clear that the Allegra Collister Nature Preserve holds an attraction for many birds, and other creatures too. Because of its value as a study site for a variety of disciplines, the BCNA has negotiated for, and administers, a conservation easement for this critical habitat. It is private property.  It is important that the landowner's wishes be respected, and the intent of the agreement honored.  Unless accompanied by an authorized BCNA site custodian, written permission must be obtained prior to entering the property.  Requests for access must be submitted, in writing, to the president of the BCNA, or to a designated authorizer / site custodian. Trespassers will be prosecuted. The complete access protocol is available upon request.

Bird Banding at Allegra Collister Nature Preserve - Fall 2004
Another bird banding season completed.  The Allegra Collister Nature Preserve has again proven to be a feather in the cap of Boulder County Nature Association.

Our banding station opened on August 30^th and closed October 23^rd.  Nets were strung on 23 days and manned for approximately 80 total hours, or an average of 3 hours 45 minutes on each occasion.

No new species were sighted or banded.

We did band 469 individuals of 48 different species.  And, that's not an accurate assessment of the overall effort involved.  Perhaps 550 birds were taken from the nets because of what we refer to as the three Rs; repeats, returns and recaptures (plus recovery if a bird is found expired).  Many birds don't learn from their first net encounter and repeat the experience on the same day, return days or weeks later, or are recaptured after being banded in previous seasons.  "Repeats" and "returns" usually are not re-recorded unless something noteworthy is detected.  "Recaptures" are always re-evaluated and the fresh data then compared with its previously collected data, if available.

This fall season, only 6 birds were recaptured and all 6 were our birds.  Two Yellow-breasted Chats, one banded in spring of 2003 and the other in fall of 2003.  Also, two Oregon Juncos, both from fall of 2003.  A Song Sparrow from fall 2003.  And, a Gray Catbird banded in the spring season this year.

Items of interest:    

• Wilson's Warbler is still the champ with the most, 144 (1250). 
• Orange-crowned Warbler remains a distant second among warblers, 43 (621). 
• White-crowned Sparrow holds the pace for overall second place, 20 (826). 
• A Common Grackle.  The only previous capture was in spring of '96. 
• Forty-six Dark-eyed Juncos is higher than usual.  Thirty-four were of the Oregon variety. 
• Two White-breasted Nuthatches!  Fall of ’93 was the only other one captured. 
• A beautiful hatch year Chestnut-sided Warbler.  That makes a total of 4 for the gulch.
• A Clay-colored Sparrow.  Fall of ’99 was the last one.  
• Three White-throated Sparrows were a nice addition. 
• And, one Broad-tailed Hummingbird.  Wish we had an 'X'band permit.  
• Long-eared Owl returned. 
• Flocks of Bushtits on two different days. 
• Haven't caught a Pine Siskin in many years.

On the summary pages, "Unidentifed subspecies" has been added as a line below White-crowned Sparrow and Dark-eyed Junco.  Several recent journal articles regarding the separation and identification of the various subspecies have caused us to be much more discerning and careful.  Our ID skills have improved significantly and birds assigned to specific subspecies are as accurate as possible.  However, in spite of the new information, we are sometimes less certain of a bird-in-hand identification.  If we are not confident of an ID, we will admit our uncertainty and record it as "unidentified".  The banding laboratory is in favor of this practice.

A careful reader may also note that corrections have been made to a few of the season or species total numbers.  It was time to have an audit completed.  Sure enough, some errors in addition were found as well as some inadvertent transposition discrepancies uncovered.  Verifying the counts all the way back to '91 was no easy task.  Its done, and we are satisfied with the results.

A few days prior to beginning banding, the banders devote time to routine maintenance at the gulch.  Weeds need to be cut, fences mended, roadside rubbish picked up and etc.  Last spring, two tarps had been folded and neatly stacked on the grasses next to the banding table.  On the first day of chores, there on the tarps lay a fair sized furry critter that appeared to have made itself a comfortable bed and was napping.  Loud noises and thrown sticks failed to arouse the animal.  Feeling safe enough to approach, the critter was then recognized as a recently deceased young coyote.  Close examination did not reveal any evidence of wounds or trauma.  No blood.  Was it poisoned?  Moments later, a live coyote was seen only a short distance away as it nonchalantly prowled the gulch.  There is no way of knowing what might have brought about the untimely death of this creature.

In early October, a passing motorist stopped when he saw us walking through the gulch.  He yelled a warning to us, "A big bear just crossed the road and went into the gulch!"  Now alerted, we were watchful; but, never encountered or saw the bear.  We often find bear scat on the trails so we know they are around.  On another October morn, banders hesitated to enter the gulch because they heard what sounded like a log and brush being torn apart by something big.  "That's a big noise!"  Better safe than sorry?  A few minutes later, nothing more was heard and/or seen in the dim predawn light.  So, full speed ahead.  The nets were opened and everyone enjoyed another routine morning at the gulch.

The Bird Banders:    Virginia Dionigi, Tony Esposito, Joe Harrison, Maggie Boswell, Tom Delaney   

Banding Summary for 1991-Fall 2004 PDF 119 kB

Sights table, Fall 2004 PDF 81 kB

B.C.N.A.
P.O. Box 493
Boulder, CO 80306