Delta Naturalists Bird Box Summary – November 2015

The original of this Bird Box Summary can be Downloaded (MS Word document, 6 pages)

Report by Jack MacDonald
Photos by Terry Carr, Jack MacDonald, Pete Blair, Peter Ward, and Geoffrey Hacker.


The Barn Owl box at Boundary Bay Regional Park was examined on October 5, and found to contain a successful nest.  In recent correspondence about Barn Owls, Sofi Hindmarsh highlighted the importance of good ventilation in the boxes, and suggested making additional ventilation holes to moderate the temperature.  Installing a temperature data logger into a box would provide valuable information.  We should consider providing better ventilation in the Tree Swallow boxes if this proves to be a problem.

October 15 saw a large crew (two Peters, two Rogers, Terry, Mike, Linda, Denny, Otto, Jack and Tom) participating in our examination and cleaning.  We did our BBRP, Earthwise and Tsa Tsu Shores boxes.  Breaking into four work crews expedited the job, and we were finished by 11:00 a.m.

 The BBRP boxes were originally constructed with 1” x 2” holes, similar to what were built and installed elsewhere.  After we realized that we had problems with House Sparrows in many boxes, especially those nearer to the homes (feed available) we installed baffles over the holes in February 2013.  These were either metal elliptical baffles, 7/8” high and about 2” wide, or metal oval baffles of the same height and width.  We also installed a few wooden triangular baffles that were about 7/8” high.  These were successful in keeping out House Sparrow, but in most cases they also prevented Tree Swallow from entering. Some boxes that were further along the dyke, away from the homes, were left without baffles.  We removed some of the baffles at the end of the 2013 season.  We started plugging holes overwinter in 2013-14, and unplugging in March after the swallows arrived, in an effort to keep out House Sparrows.

On October 16, Pete Blair, Denny Rogers, Jack MacDonald and Tom Bearss examined and cleaned the Bird Nest Boxes at Kings Links Golf Course.  All but three of the boxes contained evidence of successful nesting material by either Tree Swallows or Black-capped Chickadees.  This is a substantial improvement over last year.  Unfortunately, our two Bat Boxes and our new Barn Swallow Nesting Kiosk “Extravaganza” showed no signs of activity.  We will clean and prepare the boxes for new Spring residents in late February 2016.  At that time, we will consider options to move the unused Tree Swallow and Bat Boxes, and modify our Barn Swallow Kiosk.

On examining the boxes, in addition to finding so many successful nests, we found that several nests contained unhatched eggs or dead baby birds; several boxes had Wasps nesting inside; one unused box had owl pellets under it.  The Bat Box tree and the boxes were covered with scat; obviously a roosting tree for many species.  Rats were present in a few nests.

After seeing preliminary results, Gareth Pugh wondered how to find out why some boxes contained dead chicks every year.  He tried to find someone to test them for evidence of poison, or perhaps some other factor such as mite infestation, parent mortality or abandonment caused their death.

Tom Bearss contacted Mike Kiener at Kings Links golf course for permission to install a new Barn Owl nesting box that was constructed by our “Cascade” group (Peter Ward, Ken Hall, John Toochin, and Elsa Asadian).  It’s to be modified for improved ventilation as mentioned previously.  KL staff will be pleased to install the box and offered to reimburse Delta Nats for any material expenses.  They will dig the holes, cement the post(s) in, etc.  Mike suggested several alternatives as to where to put the box, other than along the 12th Fairway, which still could be used.  He wants to keep it as far from golfer and grass cutting activity as possible, and so do we.  A scouting trip is planned to finalize the location.



Pete Blair had previously recorded his bird box data on Cornell University’s web site, but we did not update the site with the current data because of its great data-entry requirements.  Accordingly, all the nesting box data have been consolidated into a single spreadsheet.  We collected data for 72 DNS nesting boxes on five sites and monitored 11 additional boxes or nests that belong to other organizations.  Although some boxes contained two nests, the following table shows only the contents of the top nest.2015-11-05_BirdBox_tableThe 32 DNS nesting boxes at the Boundary Bay Regional Park contained 7 Tree Swallow, 3 Chickadee, and 9 House Sparrow nests.  Twelve boxes were empty and the single Barn Owl box was occupied.  Half the boxes at Earthwise were empty, while four contained House Sparrow nests and one contained a Chickadee nest.  At Kings Links, 17 boxes contained Tree Swallow nests, 4 contained Chickadee nests, and 4 were empty.  Three boxes at Tsatsu Shores contained Tree Swallow nests while the last box contained a Bewick’s Wren nest.  The North 40 owl box was not checked this year.  Of the 73 Delta Nats boxes, 27 contained Tree Swallow nests, 21 were empty, 13 have House Sparrows, 9 were Chickadee, and three were “others”.

The 11 “monitored” sites contain boxes owned by other organizations, “volunteer” nests, or non-avian (bat) boxes.  Their contents were monitored simultaneous to collecting data for the Delta Nats boxes.

The following table shows the boxes that were recommended to be moved in the spring of 2016.2015-11-05_BirdBox_tobemoved_tableThe following table shows the boxes that require re-tagging with correct DNS ID numbers.2015-11-05_BirdBox_wrongID_tableThe spreadsheet with original data showing contents of individual boxes is available if interested.

About dncb

DNS: Delta Naturalists are a group of nature lovers whose aim is to foster interest in the natural history of the Fraser delta by sharing and enjoying nature and promoting environmental awareness and conservation. DNCB: Delta Nats Casual Birders is a group of Casual Birders who go Birding at different locations each week, usually within the Lower Mainland or in nearby Washington State.
This entry was posted in *DNCB, *DNS, Barn Owl Box, BBRP, Nestbox. Bookmark the permalink.

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