Monitor: E.A.Z. (Bet from CT)
MY MATH NEEDS TO BE DOUBLECHECKED!
I maintain two bluebird trails in rural northeastern CT (hardiness zone 5-6).
The Chimalis Trail consists of 39 boxes in a rural residential area with a mix of lawns, Christmas tree farms and meadows, with some streams and wetlands.
The Smith Memorial Trail consists of 15 boxes at a closed landfill (meadow, surrounded by woods) and transfer station.
Both trails have a mix of box styles: NABS (small and regular), Peterson (oval hole), Gilberston, Gilwood, 1 slot, 2 Rubicon, 1 GCFL, and 1 experimental NovaBird (with porch and jail dowels). Almost all are mounted on 3/4" EMT with a wobbling PVC baffle.
NEW EXPERIMENTAL TRAIL FOR 2007: In September 2006, I set up a experimental two-hole mansion trail
with 5 boxes made and donated by Linda Violett of California. The boxes are hanging from trees on a small town green surrounded by farms and residences. There were five existing HOSP-infested, pole-mounted boxes there (see photos) that I stumbled across and "claimed" (after getting permission from the Town). Bluebirds have been seen in the area. The existing pole mounted boxes are being plugged. No HOSP trapping will be conducted, in order to evaluate whether EABLs are able to secure and successfully defend the two-hole mansions despite HOSP competition. I do plan to remove any HOSP nests and eggs. I'm doing this experiment for two reasons: 1) I believe about half of serious bluebirders prefer passive alternatives to HOSP control and 2) I want to gather data about two-hole box usage by EABLs. I can't wait to see what happens, although I admit it will be hard to potentially allow some losses to HOSP, but I made a commitment to Linda to persevere. I also want to limit the variables so I can assess the two-holers. (I do use ground and inbox traps on the Chimalis Trail. No real HOSP problems on the Landfill trail as there are no houses/farms close by). Squirrels may be an issue.
TOTALS: All in all, 176 birds were fledged from 54 boxes on two trails: 53 EABL, 100 TRES, 11 BCCH, 5 TUTI, 5 HOWR, 0 HOSP. 68% of boxes were utilized by birds.
CONCLUSIONS AND SPECULATION
EABL egg viability is extremely high on my trails.
Feeding mealworms during nasty wet cold weather appears to prevent hypothermia loss of bluebird nestlings.
Over time, the total number of birds fledged is growing. However, there does not appear to be an immediate correlation between increasing the number of boxes and increasing the number of bird fledged. There seems to be a one year lag before an increase. For example, I tripled the number of boxes from 2002-2003, but the number of bluebirds fledged was unchanged, and then increased in 2004. I doubled the number of boxes from 2004-2005, and again fledging numbers stayed the same, but then doubled in 2005. Of course there were other factors at play, like weather and HOSP competition.
Controlling HOSP competition over time has dramatically reduced the number of HOSP nest attempts and interference with native cavity bird nesting. HOSP control is now in maintenance mode. I believe there is a correlation between a reduction in the HOSP population and an increase in native cavity nester fledgling numbers.
COMMENTS AND WEIRD STUFF
The first egg in 2006 was the earliest since record keeping began in 2003.
First 2006 EABL egg on 4/10, compared to first egg 4/28 in 2003, first egg 4/13 in 2004, and 4/19 in 2005.
No EABL third broods. Three second broods. (In 2004, I had several third nestings. In 2005 there were two second broods, but no third broods.)
It is possible that I had a second brood of BCCH (same box, same nest construction, same behavior by female during monitoring.) Of course I can't be sure without banding.
This box had been used in the previous year by chickadees.
The first BCCH egg was laid on 4/27. A total of 8 eggs were laid, of which 7-8 hatched and fledged (it's hard to get an accurate head count).
On 6/13 I cleaned out the box (the nest was flattened, with fecal material, no egg or nestling remains).
On 6/23, I found about 3" of moss. The first egg in this "second nesting" was laid on 6/26. 5 eggs were laid, but only 3 hatched (as of 7/20). The two unhatched eggs had incomplete pigmentation. The nest was empty by 8/4.
Note: I usually get 3 pairs of nesting chickadees on the Chimalis Trail- this was the only nesting in 2006.
I had 93% utilization of boxes at the landfill trail, in part because of a high TRES population. However, because bluebirds arrive earlier, they get first dibs. Once again, bluebirds here picked a Gilwood and a Peterson box, and also had a second nesting in a NABS box that had been used by TRES in the past. The only box that was not used by any birds was one out of the only pair I had there (a Peterson paired with a Gilwood).
Last year I got Lyme Disease. This year I got Erhlichiosis, which is another tick-borne illness (see http://www.sialis.org/lyme.htm). I usually wear DEET for my weekly checks, but seem to get bitten during irregular trail checks that I'm not prepared for (when I am driving by a box and pop out to check on it)
HOSP competition is lower than ever, with only one nest attempt (in a Gilwood box) on the Chimalis Trail in 2006 (compared to 9 in 2005.) However, I did catch 36 HOSP in ground traps throughout the nesting season, and possibly lost some eggs to an aggressive male that I was unable to trap.
HOWR populations/competition is still a serious problem. See Losses.
After repeated failed nesting attempts, a HOWR laid one normal egg and two pure white eggs. See photo. None hatched, perhaps because the nesting was very late in the season (first egg laid around 7/23). The eggs were eventually abandoned.
Lots of Paper Wasp problems at the beginning of the season, especially on the Landfill trail. Noticed European Paper Wasps for the first time. Ivory (bar) soap seems to be slightly more effective than paraffin at deterring wasp nest building, but repeat applications were needed. The problem waned as the season progressed. It was worse in boxes used by TRES.
A TRES nest used grass with seedheads! Be careful with assuming such a nest is made by HOSP.
I tried out a few experimental boxes. One by NovaBird with a porch with jail style dowels was used by a red squirrel - see report at http://www.sialis.org/mystery7.htm. A beautiful box I got from Bill Freels (with a curved white fiberglass second roof) was not used, but some claim straws were placed in it.
I tried out a nestbox cam late in the season. See http://www.sialis.org/cam.htm. Unfortunately both nests were unsuccessful. #1 - late TUTI nest abandoned. #2 HOWR nest - eggs pecked by HOWR (see video) and abandoned. #3 very late HOWR nest in a third box - 3 eggs did not hatch, nest abandoned per above. See Lessons Learned.
My husband accidentally threw out my mealworm farm and so I had to start over. The new one is smaller but I'm sick of it.=.
As the trail grows and I switch or move boxes around, it gets harder and harder to keep records and compare activity from one year to the next.
No bluebirds overwintered last year. We had a mild winter, very hot July, lots of rain during the nesting season. As of November 4 2006, bluebirds are still in the area of the Chimalis Trail.
No vandalism, even though a number of boxes are in plain view along roadways. I did write a webpage on preventing vandalism for other trail monitors.
The GFCL box hanging on my chimney (outside of my office window) was not used, perhaps because my indoor cat kept spooking birds away. BUT it was investigated by starlings, white-breasted nuthatches, bluebirds, chickadees, house sparrows and a bumblebee. Only the starlings started to put nesting material in the box, but gave up probably because of the cat stares.
Wireless would be nice. The cables are a pain to mow around.
It's hard to get a good complete view of the interior in a standard NABS box or Gilberston box with the Birdhouse SpyCam. A TX Bluebird Society box would be better (roomier and taller, also easier to feed cable out of side). Visibility on the infrared camera is great, clarity is okay.
Watching is addictive, but there is a lot of boring stuff during incubation.
I had the camera hooked up to my computer where I could capture video clips, but recording on the computer takes up way too much space. Better to put on a VCR tape so you don't miss anything.
I was surprised and how much nest building continued after the first egg is laid. I had assumed the nest was pretty much complete by then. In the HOWR and TUTI cases though it may be because they rushed with a late nesting after a failure.
Vocalizations are interesting. The female TUTI and HOWR occasionally seemed to talk to the eggs when it comes into the box.
I got to witness and record a HOWR pecking HOWR eggs - it happened incredibly fast. The peck-er proceeded to remove the pecked eggs and contaminated nesting material. Makes me wonder whether birds do the same if an unhatched eggs egg accidentally breaks in the nest. I had some unhatched eggsin nests, and they did not break or explode under nestlings.
Even though HOSP may not be nesting or even seen in the area, they may still be captured by keeping a ground trap active during nesting season.
Don't remove an inactive bluebird nest. It might get used later on.
Double check on bluebird nests after a long spate of cold nasty weather. One nest was filled with fecal glue and was sopping wet. I had avoided monitoring it because the babies were getting big, but should have done a nest change. Fortunately all birds fledged successfully, although one female was delayed by 1-2 days.
Even though a box goes unused, it may get checked out by a lot of birds (I saw this on a GCFL box hanging on the chimney outside my office window. Unfortunately, my indoor cat peering through the window scared all potential nesters off.)
Some boxes get "claim straws" or a partial nest that is never completed for whatever reason. One EABL seemed to wait until neighboring TRES finished nesting before completing their nest in a paired box.
Starling babies are REALLY unattractive. See photo.
When a TUTI flows out of the box when it is opened, it can knock it's own eggs onto the ground, where they break. Best to flush them out the entrance hole before opening.
TUTI and BCCH nests can be hard to tell apart.
TUTI: Unfortunately I do think TUTI's do prefer a nestbox mounted on a tree. This leaves them vulnerable to predation. I did have a TUTI attempt to nest in our RV electrical outlet compartment. I moved the nest to a nestbox and put it right in front of the compartment. The bird did check the nest out, but didn't lay eggs. I probably should have waited until an egg was laid to make a change.
I learned a lot, had fun and met neat people at the NABS conference (see notes).
Two pairs of bluebirds nested, with 17 fledglings. This is double the number of bluebirds produced on this trail in 2005.
Fifty-two TRES eggs were laid by 12 pairs of birds. Forty-seven of those eggs hatched, and 37 young ultimately fledged. Tree Swallows are aerial feeders, and had a tough time this spring due to extended periods of cold, wet weather.
One box produced three House Wren babies. House Wrens filled two other boxes with “dummy nests.” These are fake nests made of sticks, which are used to keep other birds from moving in on their territory.
SUMMARY OF LOSSES
No adult birds were lost that I know of.
Suspect that at least 3 TRES eggs in one nest were lost to a male HOSP I was unable to trap. Possibly the same bird also destroyed 3 TUTI eggs in an abandoned nest.
36 HOSP trapped with Van Ert and DRST ground trap on the Chimalis Trail. (Compare to 25 HOSP trapped in 2005). However, there was only one nest attempt (failed due to inbox trapping.)
There were no HOSP on the landfill trail (houses and farms are too far away, landfill is surrounded by woods.)
Since I still get HOSP in ground traps, but only had one HOSP nest attempt this year, I wonder if my trapping efforts in past years have removed the HOSP that were programmed/inclined to nest in boxes.
Six dead TRES nestlings (13%) in two boxes at landfill trail of unknown causes. (Compare to 40% losses in 2005). All boxes had kerfs, so it is not believed to be a toehold issue. 1 dead TRES on the Chimalis trail.
Two TRES nests removed by HOWR.
Possibly 3 TRES eggs in a third box lost to HOWR. (TRES successfully renested in that box.)
3 HOWR eggs pecked by HOWR - caught on a nestbox cam - see video
QUESTIONS FROM 2005
Are bluebirds starting nests earlier and fledging later in the season? Answer: Need to evaluate this over at least a 5 year period, but it appears that first eggs are coming earlier. This may be due to climate change, or may be due to experienced, older returning birds.
Why did so many TRES nestlings die on the landfill trail? 2006 Answer: I'm guessing weather, as the same number of losses were not seen in 2006. However, the one brood lost was in a box where an entire brood was lost in 2005, so perhaps there is some problem in that area/box.
Is it worth the time, effort and ick factor to raise mealworms? 2006 Answer: They are so expensive, that I guess it is. As noted above, my husband accidentally threw my farm out so I had to start over. Also, all the beetles died during the cold weather (I keep them in an unheated room inside the house.) See http://www.sialis.org/raisingmealworms.htm for info.
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