Many bird species, from wrens to woodpeckers, owls and even ducks, nest in tree cavities. Woodpeckers, nuthatches and chickadees excavate new holes every year in decaying and dead trees, leaving their previous ones for other cavity-nesting birds and animals to use. These nest sites can be lost as trees are removed from woodlands and yards for buildings, gardens and recreation. As development increases in our community, fewer trees and cavities are available for breeding birds and their populations decline. Providing birdhouses for them to nest in can help to reverse this trend.
We can attract different species by providing various types and sizes of birdhouses for them. There are many designs available in books and websites; however, although decorative, they may not be suitable cavity nests in nature. Birds choose their nest sites based on their breeding habitat requirements such as location, tree species, cavity and hole size, height, aspect, available food and predators. An abundance of websites provide information on design and dimensions important for common species. You can use extra lumber, bark, woody debris, recycled materials, PVC pipe, etc. but the nest box needs to be strong, weatherproof, ventilated, accessible, securely mounted and functional. The nest box can be suspended or mounted on a tree, a pole, or below the roof of a building; however, it should be free from wind, rain, all-day sun and significant disturbances. Materials that can conduct heat or toxins are unsuitable. An important consideration is an entrance hole of the correct size. Birds prefer a nest hole just big enough for them to enter. Birds prefer a clean empty box they can line themselves with a special nesting materials so old nest material should be discarded to eliminate decay or parasites.
It is important to protect your birdhouse from predators. Perches at the entrance hole can provide access for other birds or animals. Placing the box well away from other trees and shrubs prevents squirrels from jumping to the birdhouse roof. Inverted cones and metal strips wrapped around the the pole are examples of predator guards.
The Birdhouse Building Contest!
There will be 3 judges:
- Hans-Christian Behm, builder and wood craftsman;
- Graeme Dinsdale, nature buff and bird aficionado;
- Myself, Billi Gowans, bird biologist.
Two age classes will be judged: adults and children (≤12 yrs). Prizes will be given for 1st, 2nd and 3rd place. Winning birdhouses will later be published in the Undercurrent newspaper. Judging criteria includes 2 main categories, each with 5 subcategories, worth 10 points. The result is an overall score up to 100 points for each birdhouse. The criteria are as follows:
- Design – Is the design bird-oriented and suitable for a particular bird?
- Aesthetics – Does the construction have proportionate and attractive form? Did it take ingenuity?
- Materials – Are the materials natural? Are they likely to introduce toxins? Where did they come from? Are they recycled?
- Quality – Is the birdhouse solid, substantial and likely to last several years of use?
- Maintenance – Is the birdhouse accessible and easy to maintain inside and out?
- Species – Is the birdhouse for a particular species? If so, what species?
- Dimensions - Are overall size, height, depth and width suitable for a particular or the intended species?
- Entrance – What is the size and shape of the hole? What is its position on the birdhouse?
- Function – Does the overall design promote its use by a local species? How will it attract a cavity-nester?
- Intended Location – Where will it be placed; habitat, aspect or height? Would it be accessible to predators?
Contest questions can be addressed by calling Josephine Riley at 604-947-0747. Local bird enthusiasts, nature groups and the wealth of internet resources can help you with birding questions. After the contest, judges will enthusiastically provide guidance where we can.
The Bowen Island Conservancy encourages you to participate in the birdhouse contest as a way of contributing personally to biodiversity. A wave of new birdhouses in our rural landscape could boost the success of breeding birds on Bowen Island. Your nests can be reported to important local and provincial databases of bird behaviour and populations. Think of the wonderful observations everyone can have of birds building nests and busily feeding young, and those cute, fuzzy new fledglings!
I look forward to your wild nest creations!Billi Gowans