2-Holed Mansions
in Connecticut
2-Holed Mansions
in Connecticut
Test on Bet Zimmerman's Trail
Year 2007
Western Bluebirds on my California trail learn to control 2-Holed Mansions without the need for me to trap House Sparrows. This experiment was intended to see if those results could be duplicated on an Eastern Bluebird trail by having an Eastern Bluebird monitor duplicate my trail conditions using 2-holed boxes.
Bet Zimmerman of Connecticut agreed to place 2-Holed Hanging Mansions on single-box sites (2 acre forage territory per box) and follow the "Possible Keys to Success" per my web page at: http://home.earthlink.net/~lviolett/keys.html.
No trapping of House Sparrows (HOSP) was to be done and no gadgets to deter HOSP was to be added. The 2-holers had to stand on their own merits (as they do on my trail) without any monitor interference except removal of HOSP nests and eggs.
However, by the second year (2008) there were more 1-holers at the site than 2-holers. Boxes with one hole are too dangerous in areas with House Sparrow infestations with or without trapping. That is already well known. This is one more example of a poorly-configured test site with boxes too closely spaced and undesirable results from 1-holers confounding overall results. Even so, Eastern Bluebirds were able to fledge chicks from a 2-holer amongst House Sparrow competition before 1-holers outnumbered 2-holers during the second year (2008) at that location.
Correct Spacing is Critical to Outcomes: Doubling up boxes in a Bluebird territory does not result in twice the number of Bluebirds fledged from a site. It results in Bluebirds not being able to defend both boxes from House Sparrows. And if Bluebirds can't defend all the boxes within their territory, House Sparrows have a much greater opportunity to come in and cause problems. Easy to understand. And that's why I specify that well-spaced 2-holers and only 2-holers be used at test sites.
Bet's logs state: "Measured distance between boxes, approximately 300 feet except for 150 feet between H-12 to H-10 and H-11 to H-10. Box 6X is 50 feet from H-10, 200 feet from H-9."
Translation: Every box has some other box within 300 feet and a 2-holer (H10) was placed only 50 feet away from a 1-holed box where homeowners have allowed House Sparrows to nest. Standard spacing for Bluebird boxes is 300 feet from one another to allow a territory of two acres per box.
EXTRA BOXES: In 2008, someone re-opened six MORE 1-holers amongst the 2-holers. Not only did this skew results, the poor performance of the 1-holers at this no-trap site was included in the summary of site performance (see http://www.sialis.org:80/picturehospkill.htm).
Bet Zimmerman's notes at http://www.sialis.org/trailhilllog2007.htm. were used to create a side-by-side visual table (below) for an overall look at the first year activity in all the boxes before the test site was inundated with 1-holed boxes the following 2008 test year.
DATE
H-9
(2-Holer)
200 feet from the 1-Holed Nestbox
Homeowner 1-Holer 50 feet from H-10 and 200 feet from H-9
H-10
(2-Holer)
50 Feet from 1-Holer and 150 Feet from H-12
H-11
(2-Holer)
150 Feet from H-10
H-12
(2-Holer)
150 Feet from H-10
Winter (Jan-07) Acorns ? -0- -0- -0- 3/11/07 1/2" HOSP nesting material (left as-is to verify) HOSP nesting material removed Acorn Shells Acorn Shells Male Bluebird in tree 3/16/07 3" HOSP nest material (left as-is to verify) 3" HOSP (left as-is) -0- -0- -0- 3/24/07 Completed HOSP nest with lots of grape vines (left as-is to verify) HOSP pair flying away from box. Nest removed. Acorn Shells Bluebird pair in tree
-0- -0- 4/5 & 4/7 HOSP Nest Removed (no eggs) Male in Box HOSP Nest Removed
-0-, little grass Bet saw box on very low limb during a drive-by & stopped to rehang
HOSP Nest/no eggs (assumed removed)
-0-, little grass 4/13/07 Some HOSP material removed Little grass removed Some shells (acorn) Box hung higher Lifter broke, no check 4/22/07 1" Nesting Material left as-is to verify Little HOSP material removed -0- Same nest material left as-is to verify -0- 4/28/07 HOSP nest (no eggs) removed 1" HOSP material removed -0- Tufted Titmouse (seen) building nest. Hole Reducer to protect TUTI Recommended but wasn't added.
Grass & Moss
5/3/07 HOSP nest (no eggs) removed 1/2 HOSP nest (no eggs) removed -0- Tufted Titmouse still building nest HOSP material over moss; left as-is 5/6/07 HOSP nest (1 egg) removed 1/3 HOSP Nest; Added 1.25" thin metal hole reducer to deter HOSP at 1-holer. -0- TUTI nest (no nestcup) HOSP? nest (left as-is to confirm) 5/8/07 HOSP nest (no eggs) removed One piece of grass removed. -0- TUTI nest (no nestcup) HOSP? nest (left as-is to confirm) 5/15 & 5/16 HOSP nest & 4 eggs removed Wren sticks TUTI nest (no eggs). 1&1/4" Thin Wooden Hole reducers added. HOSP nest & 1 egg (removed) HOSP nest & 1 egg (removed) 5/19/07 -0- Moved box a few trees further north
HOSP 3 eggs (removed) TUTI nest (no eggs). HOSP nest & 2 eggs (removed) -0-
5/26/07 -0- HOSP nest & 2 eggs (removed) HOWR sticks over TUTI nest HOWR sticks, removed all and found 2 old TUTI eggs under nest HOSP nest (no eggs) removed 6/2/07 Several inches fresh green leaves (left as-is) HOSP Nest (no eggs) removed HOSP Nest (no eggs) over old TUTI base. HOSP portion removed. -0- HOSP nest, 5 eggs removed 6/9/07 Flying Squirrel came out of box HOSP Nest & 5 eggs removed No change Few grass pieces -0- 6/16/07 Just leaves 1" HOSP material removed Removed old TUTI nest base & hole reducer -0- -0- 6/22/07 Chunks of grass w/leaves 2 HOSP eggs/nest removed -0- 1" HOSP material removed -0- 6/30/07 -0- 1/4" HOSP/egg removed (male on roof) -0- -0- EABL tall nest & 1 egg 7/6/07 -0- HOSP Nest (no eggs) -0- -0- 3 EABL eggs (incubating) 7/14/07 More grass w/tunnel; Flying Squirrel inside 5 HOSP eggs oiled by monitor "to avoid harassment of Bluebird nest" -0- -0- 3 EABL eggs (incubating) 7/21 & 7/22 Not Disturbed Oiled eggs gone, bigger nest (removed) -0- -0- 2 EABL chicks 7/28 & 7/29 No Squirrel seen -0- -0- -0- 2 EABL chicks, only female adult seen (single?) 8/5/07 -0- -0- -0- -0- EABL Fledged HOSP Eggs laid in each box during 2007 = 5 HOSP Eggs (2-holed) 18 HOSP Eggs (1-holed post-mounted box) No HOSP Eggs (2-holed) 3 HOSP Eggs (2-holed box) 6 HOSP Eggs (2-holed box) End of 2007 Data Eastern Bluebirds successfully fledged chicks during the first test year (2007) from a 2-holer in this House Sparrow infested area without the monitor having to trap and without using gadgets such as spookers or monofilament. The test, as far as Bluebirds being able to outcompete House Sparrows in 2-holed boxes was successful.
In 2008, an unknown monitor unplugged six or seven post-mounted 1-holers in close proximity to the 2-holed boxes. Standard 1-holed boxes perform poorly amongst House Sparrows, yet, performance of those 1-holers was included in Bet's conclusions (see http://www.sialis.org:80/picturehospkill.htm). Below is a photo of Bluebird chicks killed in a 1-holed box at this test site.
It is well documented that boxes with only one hole are too risky to put in areas with heavy infestations of House Sparrows.
No Bluebirds were usurped or killed by House Sparrows in the 2-holed boxes at this test site.
The 2-holed boxes allowed Bluebirds to fledge chicks at this site in the midst of House Sparrow competition without trapping and without using spookers.
The 1-holed boxes had Bluebird chicks killed by House Sparrows in spite of the addition of spookers and monofilament to deter House Sparrows.
An interesting observation from the 2007 data is that House Sparrow activity was significantly greater in the (lower) post-mounted 1-holed box than in any of the hanging 2-holed mansions.
Following is an excerpt from Bet's web site http://www.sialis.org/hosp.htm regarding House Sparrow control
"If a HOSP shows an interest in a box that bluebirds have claimed, immediately lower the height (temporarily) of the bluebird house to about 4 feet. Put up another house a few feet away at a much higher height (around 7-9 feet) and if possible closer to a nearby house or other man-made building. The House Sparrow will often move to the new, higher house. This can facilitate inbox trapping."
This experiment seems to show that House Sparrows preferred the 1-holed post-mounted box over (higher) hanging 2-holed boxes. The reason for the preference is not known.
MAINTENANCE: Hanging boxes do not require the trouble and expense of post equipment. The only box maintenance necessary is to periodically check to make sure that the 1/4" hanger rod piercing the roof (secured with lock nuts) is nice and tight and to prune branches so there is a clear path to lift the box up and down through the tree.
Bet and her husband, Doug (pictured) preferred using a ladder rather than a pole to lift boxes into the tree.
TRAPPING: These boxes can be used in conjunction with trapping. At test sites, however, no trapping is permitted. If trapping and other gadgets or techniques (pairing) are implemented in conjunction with 2-holed box experiments, successes tend to be credited to monitor actions rather than Bluebird actions.
Trail Details:
Bet did a great job of documenting 2007 events with photos. Only three eggs were seen in the Eastern Bluebird nest and close (zoomed in) inspection of the egg photo shows what looks to be a tiny spot (hole) in the upper egg and small (non-pierced dent) in another. There were House Wren problems in a nearby Titmouse box and that could explain why only three eggs were in the nest and why only two eggs hatched.
Another interesting observation is that Bet's notes refer to the nest in this deep box as being "tall". Some monitors don't build deeper boxes because they think Bluebirds will simply fill the box with a high nest and, thus, negate any advantage of building deep boxes. Notice in the two photos (below) that only the side rim of the nest is tall. The second photo shows chicks snuggled deep within the nest center so that they are within a couple of inches of the floor. (The label at the back of the box in the first photo will give perspective to the relationship of the chicks to the floor in the second photo.)
Home
