WHAT A SEASON! – WOOLWINE HOUSE BLUEBIRD TRAIL — WOO-HOO FOR BLUE!
The TRAIL FINAL RESULTS FOR 2012 – SEPTEMBER 4, 2012
Here is final data, interesting observations, and highlights for 2012 nesting season on the WHBBT. Only two species nested and laid eggs and fledged young:
Eastern Bluebirds: 30 nest attempts, 128 eggs laid, 100 eggs hatched, 87 fledged. 13 nestling deaths, 19 unhatched and retrieved eggs, 9 missing/destroyed eggs.
Carolina Chickadees: 3 nest attempts, 15 eggs laid, 15 hatched, 14 fledged. 1 nestling death.
Results of Predation, Deaths of Nestlings, and Missing/Destroyed Eggs: 1 snake, several house wren attacks, chickadee nest takeovers, a 3-night freeze snap early in season, and 2 predations are “unknown” reasons: possibly flying squirrel, snake, starvation/abandonment (death of one or both parent bluebirds), or death due to excessive heat, or house wren—I could not determine cause in two cases. Chickadees also took over 2 bluebird nest attempts in early season—they destroyed bluebird eggs and nested over those bluebird nests (eviction).
Eggs Missing/Disappeared inside nests: 9 eggs unfound or unaccounted
Unusual Observations/Results on the trail for 2012: What surprises me the most this year is the number of nestling deaths and unhatched eggs! …. fourteen (14) dead nestlings and nineteen (19) UNHATCHED eggs, all retrieved by me during the nesting cycle or after nesting cycles were completed and soiled nests removed and dissected and nestboxes cleaned out. The rest of the eggs were missing/unaccounted for.
The Good News: I again fledged more bluebirds this year than the year before. It has been consistent that I fledged on or about 20 more bluebirds per year since my bluebird trail officially commenced in February 2008’s nesting season. My records show a number fledged for 2008, and then 20 more bluebirds fledged in 2009, and then approximately 20 more in 2010, and again in 2011. I went from 14 nestboxes in 2008 to 19 presently. I installed two more nestboxes in early July this year to bring the count to 21 nestboxes on the trail for 2012; however, House Wren dummy nests were built in those boxes, so that data is not included for this year. For 2012, I fledged 11 more bluebirds than last year. I strongly believe that the number of nestling deaths (14), the number of unhatched eggs (19), and the fact that one very successful nestbox in past had to be removed after the first brood fledging because of that location turned into new a construction site made an impact on the fledging totals this year. I was honestly expecting a larger number of fledgings of bluebirds this year. Considering it’s still 11 more than last year makes me feel satisfied.
What I have learned, will continue doing, and will do differently:
1. Blowfly Deterrence–a chronic issue on the trail: I will continue my careful application of diatomaceous earth to the bases and centers of nest materials in completed nests, BEFORE eggs are laid if possible. I will continue this successful method along with creating hardware cloth bases for ALL nestboxes for future years. Note: The hardware cloth bases will be added after a partial nest is started or after completion of a nest. I will not leave them inside vacant nestboxes. The reason behind this is so that the female will not be confused by the bases. The purpose of adding them is for air circulation on the bottom of the nesting material in nests infested with blowfly larvae. This will also give me access to brushing out dead larvae that fall through the bases to the wood floors underneath.
2. Monitoring: I will continue, if possible, twice-a-week monitoring–all will depend on weather and other factors, of course. This is the ideal schedule for me. I get accurate records (those dates!) and better chances to troubleshoot issues and problems and possibly be able to save baby bluebirds by doing so instead of ONCE a week. This is not always possible for every nestbox, and I’m happy with once-a-week checks. Experience has told me how I lose control of monitoring nesting cycles if I let two weeks pass by without checks. This will happen “once in a blue moon” due to illness or severe weather. Another goal for monitoring is to find a back-up person who knows my trail in advance and is willing to step in and help me monitor in the event I cannot (such as hospitalization, as an example). I plan on contacting the Virginia Master Naturalist program in my area to get a volunteer or two who is looking for building up their own volunteer hours for certification in the program. See info on the Virginia program here: http://www.virginiamasternaturalist.org/
3. Installations of More Nestboxes: The trail is expanding! I expect to have 30 nestboxes for 2013, and will expand to 40 nestboxes by 2014–IF THAT IS POSSIBLE (that’s the key!). I will stop at 40. I cannot effectively monitor more than 40. I may find 30 is my limit. At that time, and I know I have my limit to what I can take care of, I will conduct further outreach to train others to monitor the boxes by themselves on their own premises and to just submit their data to me. I am realistic about this–as much as I encourage it and I will train, I do not want anyone to feel “obligated” — this is a big commitment. However, a back yard bluebirder who has one or two nestboxes will find it’s not as complicated as it seems at first–usually they will find they get great joy out of doing it through a little experience, and that it is fun! If two predator guards are used, there will be less risk to the birds and more success in monitoring the birds, as opposed to finding deaths due to predation (which is not pleasant to deal with, no matter what the predation is). My point still stands: Manmade nestboxes is not true nature. A natural cavity is. If man puts up a nestbox and invites birds to use it, it is my position to make it as safe for the birds for DETERRING predators and not inviting predators to get the birds. What is the point of taking effort to put up housing and then setting the birds up to fail at successful breeding? The purpose in this effort is “bluebird conservation”. ADDITIONAL COMMENTS: I assure you if I had too many failures in fledging baby bluebirds, I would not be doing what I am doing today. That is how I know deterring predators is the right thing to do. Natural cavities also have predators, but man cannot and is not involved in that true setting of nature. That I accept when it comes to bird losses. However, it’s been proven for many years now that the bluebirds have suffered through the years, their numbers declined almost to an extinction, in past. It hasn’t been until the 1970’s when the nestbox projects took off that bluebirds have proven to come back to healthy numbers. That math is good enough for me. It is not just the loss of habitat to building of housing developments and sprawl, removal of snags on farmland, parks, meadows, and even back yards, usage of pesticides and herbicides (RoundUp) killing adult birds and young or causing them to hatch deformed — but it is the introduction of non-native species of birds — The English House Sparrow and the European Starling that prey on our native cavity-nesting birds, destroy their eggs and young, and take over the natural cavities that do remain in North America. The starlings will strip all fruit food sources in minutes from a tree or shrub. Read on more about this here: http://www.nps.gov/miss/naturescience/bluebird2.htm
4. Nestboxes in Afternoon Shade! This is my #1 priority for future installations–if it is possible for the new sites. After this horridly hot summer in Southwest Virginia, I saw nestlings suffer in the heat, attempting to breathe and keep cool. Thankfully, I did not have many nestling deaths due to the heat. Good ventilation in the nestboxes is the reason most survived. I will also make a few heat shields for 2013 to have ready for emergencies. I will try to make them inexpensively but easy to install for the few boxes in full sun in the event of excessive heat. By installing future boxes in afternoon shade, I can eliminate this problem altogether. This is why I want to get my boxes installed this month–while the leaves are still on the trees and I can see where the shade will fall. Installing heat shields is only a last resort. The less boxes in full sun, the better, as far as I’m concerned. This is not always possible, however.
Summary Observations and Tidbits:
This has been the most challenging year yet on the Woolwine House Bluebird Trail regarding observing and troubleshooting unusual activities. I dealt with absolutely zero blowfly infestations during the first two broods (usually in my location it’s every brood–no matter what time of year) and then third broods got smacked hard with a super-strong and powerful blowfly population—as if they were on steroids. Other problems were ants attempted to infest one nestbox (and corrected by me), excessive heat caused some weakness and slower development even in well-ventilated nestboxes (but no deaths due to heat), a freeze snap for three nights in a row in early Spring caused starvation due to lack of insects (and thus protein and hydration to one hatchling—that is the only death to the cold snap), one snake managed to get past a stovepipe guard (this happens at least once each year), a couple of House Wren attacks at a location of two nestboxes, chickadees fighting bluebirds over nestboxes at a location of two nestboxes—chickadees destroyed bluebird eggs; and last but not least, there has been an unusual number of nestling deaths and unhatched eggs. One nestling death was a chickadee–all chickadees in that brood fledged except one—could not determine cause—no blowfly larvae found—possibly starvation. Out of 19 nestboxes on the trail, three were unoccupied this season. Surprisingly, two of those three unoccupied nestboxes were very successful last year in fledging birds and the years before (average 2-3 broods fledging bluebirds). Therefore I will not move these two boxes for 2013. I was able to keep blowfly infestation controlled in all boxes except for two nests. One brood of 4, in spite of my method of control, did not succeed–the infestation was too large and larvae too strong and thus survived deterrence—those 4 nestlings died quickly from weakness due to anemia (low blood cells) thus disabling them (weakness) to take in food from the parent bluebirds before I could save them. Upon dissecting the infested nest, I counted quite a few live, gorged-with-blood larvae. The other nest showed the same symptoms, so I conducted a nest change-out—this is moving the weak nestlings carefully by hand from the infested nest to an unused-unsoiled-abandoned previously built nest by bluebirds made of grasses– those nestlings survived the nest change and fledged at age 18 days old. I dissect all nests, except unused nests which I keep for emergencies. By dissecting used, soiled nests, I find interesting things about them, how many blowfly larvae survived my deterrence method, how many did not survive, how many infested the nest, finding uneaten food given to the fledglings but not consumed at fledging time. This year a dead baby skink or newt and a large dead bumblebee were found on top of the fledged nests. I also had two nests with the same parent bluebirds, one brood after the other, that appeared to be completely unskilled (lazy?) at removing the fecal sacs left by their nestlings and upon cleaning out the nestbox, I found those nests severely crusted with the nestlings waste matter—wet and sticky. I was surprised to find the nestlings fledged, but they did. I look at the sides of the walls and the front of the box for clues of successful fledging.
The following nestboxes are worth mentioning certain observations:
Interesting Data – Nestbox #1: The first bluebird brood’s 4 eggs were pushed down inside the nest by something I have not been able to pin down. It appears to have been another bluebird female that wanted to use that nestbox—evicted the other female or perhaps the first female abandoned the nest or was killed. The eggs were not destroyed, and I was able to retrieve them upon cleaning the nestbox after the nesting cycle was completed.
Interesting Data – Nestbox #3: This box has been very successful with 2-3 broods consistently, except this year—it was completely unoccupied. I have not been able to determine reason. It will not be moved for 2013.
Interesting Data – Nestbox #7: One brood of three nestlings died inside the nest—do not know why; possibly the parents were killed and the nestlings died of starvation. Interestingly, I discovered this data late as I left the nest in the box thinking the female would come back and lay a new clutch. At first look inside the nest, I thought a snake had taken the nestlings. It turned out they died inside the nest, and were “covered up” by some nesting material. Because of the age of the deaths soon after hatchling (1-2 days), they could not be seen when I looked upon the nest with my mirror. It wasn’t until I removed the unoccupied nest a month later that I found the dead hatchlings while dissecting the nesting material.
Highlight – Nestbox #8: This nestbox was unoccupied by any species for two years straight. Instead of pulling it up, I decided to give it another chance this year; I knew it was in great bluebird habitat. This year, my hunches were correct–it produced THREE broods this year, though one brood had a clutch of 4 unviable eggs laid on or before July 24th and thus never hatched as of August 31, 2012. Those four eggs have been included in the unhatched egg count total for this nesting season. I “candled” the 4 eggs—all were clear showing no development; therefore it appears they were unfertilized.
Interesting Data – Nestbox #9: This has been a successful box since the day it was installed. This year, one brood fledged and the box had to be removed due to the location going under construction; therefore, no more data of fledged birds could be included from that nestbox in this year’s eggs and fledgings count.
Interesting Data – Nestbox #10: Strangely, this box did very well in past two years. This was the nestbox that fledged 2-3 broods of chickadees and bluebirds, including the laying of my first ever clutch of white eggs. This box was totally unoccupied this year. The good habitat for bluebirds has not changed. The box will remain to see how it does next year.
Interesting Data – Nestbox #12: This nestbox has been consistently my highest yielding of bluebirds in years past. This year, we had some troubles. First brood had one unhatched egg; the rest of the nestlings were taken by a snake–first time for this box to have snake predation. The second brood had one unhatched egg; the rest of the nestlings were attacked by wrens. One nestling was taken out of the nestbox and dropped, which ended up in the Noel guard and, unfortunately, died there. The other two nestlings survived the attack inside the nest and fledged. Both incidents this year is very unusual for this nestbox, which is in open habitat with beautiful white pines trees in front of it–not close to brushy areas, which attracts the wrens.
Interesting Data – Nestbox #13: This was a good box for bluebird habitat and had successful bluebird fledgings until past two years. This being a hay field, the growth of vegetation surrounding the field where the box is located has caused too much thickets nearby. In spite of my two years of efforts keeping this nestbox trimmed of overhanging tree branches and vegetation growth, including fast-growing Morning Glory, I cannot maintain this box any further and keep those thickets trimmed away from the nestbox. It will be moved to a new location for 2013 to attract bluebirds in better, more open habitat. It is obvious the bluebirds did not like this nestbox being close to thick vegetation and hay grasses being too tall for long periods of time, which makes it more difficult for parent bluebirds to stay close to the nests to find insects (bluebirds go to ground most of the time to pick up insects off the ground).
Highlight – #15: The same nestbox had the earliest egg laid on my trail— two years in a row: March 11 in 2011 … and March 8 in 2012. This nestbox truly has become the most successful nestbox on the trail today. It makes me ponder if this is the same bluebird couple this year from last or perhaps bluebirds that fledged from it last year returned this year early to raise families in it.
Highlight — Nestbox #16: The 3-Year Test-Two Hole “Mansion” (from Linda Violett, Yorba Linda, CA) was a MAJOR winner this season! – THIS YEAR, absolutely no House Sparrows (HOSP) attempted to nest in this area where the HOSP built nests and laid eggs (removed by me) in 2010 and 2011 which later bluebirds fledged one brood each year — this without me intervening with gadgets like Sparrow Spookers or HOSP trapping. A total of 12 bluebird young fledged this box this year, in spite of a blowfly issue in one nest and house wrens entering the nestbox while the bluebirds babies from Brood 3 were attempting to fledge. My first bluebird nesting material dropped inside was discovered on March 16 with a partial nest built. The first egg laid was March 27th. The third brood bluebirds fledged on August 14th! This is 5 months of bluebird activity! More information in detail and a summary report will be coming to the website to conclude this 3-year test, written by Linda Violett and me. I expect to have this online by end of September (or sooner). I have many thanks to make: to the homeowner who supported me in this nestbox project and to Linda Violett for mentoring and supporting me during this test. The nestbox will remain for 2013, with permission by the homeowner. This nestbox has proven to be the second most successful on the trail, not far behind Box #15 as the top producer of Eastern Bluebirds on my bluebird trail!
See my 3-year test results and Linda’s comments on the Violett’s Bluebirds website here: http://home.earthlink.net/~lviolett/testwoolwine.html