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SIZE OF BOX TEST (Dick Purvis)

 

Dick Purvis (Bluebird Coordinator of Orange County, Calif.), thought that a larger box interior was of greater benefit to bluebirds during a battle with HOSP than the second (escape) hole. 

To test the large box theory against the escape hole theory, I provided Dick with three large boxes with 2 holes and three large boxes with only 1 hole.  He agreed to place all six test boxes at his worst House Sparrow/Bluebird competition sites.

 

 

 

Dick's preferred nestbox style is a standard 1-holed box.  Unfortunately, he mixed standard-sized 1-holed boxes into the test mix and sometimes even took down successful 2-holed boxes and replaced them with 1-holed standard boxes (Dick's mixed notes are provided at the end of this web page).  I've pulled the 2-holed results into a segregated tabled format so readers can see the good results of having an escape hole.

  Test Results:

2-holed boxes were successful by all performance measurements in relation to HOSP/bluebird competition and outperformed 1-holed boxes regardless of box size.

  • 2-holed boxes, when left in place, were successful in Dick's test (100%)

  • No Bluebird nests in 2-holers were usurped by House Sparrows

  • No Bluebird adults, chicks or eggs were lost to HOSP in any 2-holer

  • HOSP usurped all other box styles (other than 2-holers) at least once during the test

 

Dick stated that events at Schweitzer Park (a battle between HOSP and bluebirds for a 2-holer, " . . .  was the first time I have ever seen bluebirds win the battle over sparrows." 

 

 

Loc. / Problem Site  Results WEBL?

HOSP?

Notes / Comments  
SCHWEITZER (one box)

2001 =  HOSP & WEBL fighting over standard box.  Dick replaced the standard box with 2-Holer during the HOSP battle.  Bluebirds won the battle in the 2-holer.

WEBL fledged from  2-holer.  Then HOSP moved in & laid eggs. (Emptied).

Then 1/2 WEBL nest

WEBL Fledged HOSP tried after WEBL fledged Purvis says " this was the first time I have ever seen bluebirds win the battle over sparrows."   

Log dates were not provided so we do not know if HOSP took the box immediately after WEBL fledged.. After HOSP were evicted, bluebirds reclaimed the box.  The unfinished bluebird nest was most likely too late in the season to complete.

 
           
HART PARK;  3 Boxes

2001 = 2-holer and  large 1-holed box hung at HOSP problem site

5 successful WEBL nests WEBL Fledged   Both experimental large boxes were successful  
           
AMERIGE PARK;  1 Box

2000 = 2-holer hung at HOSP problem site

2 Successful WEBL nests WEBL Fledged   2-holed box successful  
           
FORD PARK;  1 Box

2000 = 2-holer hung at HOSP problem site

2 Successful WEBL nests WEBL Fledged   2-holed box successful  
FORD PARK;  1 Box

2001 = 2-holer (see prev. yr.)

 

Purvis removed 2-holer when he saw a HOSP nest    HOSP nest. It was not noted whether there was bluebird competition.  HOSP nest should have been removed and box left in place.  
           
BOYSEN;  1 Box

2001 = 2-holer hung at HOSP problem site

Purvis removed 2-holer when he saw a HOSP nest   HOSP nest. It was not noted whether there was bluebird competition.  HOSP nest should have been removed and box left in place.  

 

 

A major concept to the success of 2-holed boxes is that bluebirds gain confidence battling House Sparrows as time passes.

Unfortunately, Dick removed some boxes when he saw HOSP appear, and he removed some successful 2-holers and put BACK standard 1-holers the following year. 

Purvis's complete report of 11/1/01 (including 1-holed box results) is presented below.  Results of 2-holers are underlined and in bold.


Here are the final results of my testing large boxes versus standard ones: 

Ford Park, 1 box 
1999 severe HOSP problems. 
2000 replaced with 2-holer. 2 successful WEBL nests 
2001 HOSP nest. Took down 2-holer.
Put up standard box 1 block away. 
one WEBL nest fledged. Then HOSP nest. Took down box. 

Amerige Park, 1 box 
1999 severe HOSP problems 
2000 replaced with 2-holer. 2 successful WEBL nests. 
2001 replaced with standard box. 2 WEBL nests. No problems 

Schweitzer Park, 1 box 
2001 standard box. HOSP nest with egg. HOSP/WEBL fighting.
Replaced 
with
2-holer. WEBL nest - fledged OK. HOSP nest with eggs. Emptied. 
1/2 WEBL nest. No further activity. 

The Schwietzer
Park event was the first time I have ever seen bluebirds win the battle over sparrows.  

Hart Park, 3 boxes 
2000 HOSP problems at 2 boxes. 
2001 replaced 2 boxes with 1-holer
and 2-holer. 5 successful WEBL nests.

Boysen Park, 1 box 
2000 standard box. HOSP nest over WEBL nest. Moved box. HOSP nest. 
took down. 
2001 put up large 2-holer. HOSP nest. Took down. 

Koch Park, 3 boxes with previous history of HOSP problems 
2000 3 large boxes replaced standard boxes. 5 nests. No HOSP problems 
2001 3 standard boxes replaced large ones. 6 nests. Probably no HOSP 
problems. 2 nests - all young dead. 1 nest bad eggs. 

Oak Knoll, 1 box 
2000 standard box, HOSP problems. Paired box. WEBL OK in one HOSP in 
other. 
2001 replaced with large 1-holer. HOSP and WEBL fighting. HOSP won. 
paired with standard box. HOSP took both. Took all down. 

Juarez Park, 1 box 
2000 standard box. HOSP problems. Took down. 
2001 large i-holer put up. HOSP nest over WEBL nest. Cleaned. Box stolen 

These results seem to be somewhat mixed although there may be an advantage for the large boxes. The Schwietzer
Park event was the first time I have ever seen bluebirds win the battle over sparrows.  

[End of Dick Purvis 11/1/01 report]


 

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As of June 15, 2012