Will predators attack your swallows?
There's always danger of predation, so protecting your nesting birds is a
crucial responsibility for you as a project manager.  Finding boxes emptied of
young and discovering discarded wings, such as the bluebird wing below, is
terribly disheartening.  You must take steps to reduce chances of this
happening.  Careful choice of project site and proper location of boxes
greatly reduces risk of predators finding your boxes, but you should also try
to prevent predators from reaching any boxes they do happen to discover.








What animals predate nesting Tree Swallows?
Raccoons, opossums, weasels, and cats will kill and eat any adults and young
they can pull out of boxes.  Raccoons are especially dangerous because if
they find one box and predate it, they look for other boxes and may predate
every box in a project.  Most snakes can't climb poles, but a few species can,
and will enter boxes to eat eggs, young or adults trapped inside.









How can you stop a predator from reaching a box?
Make it as difficult and unpleasant as possible!  The best method is to attach
a predator guard to the pole below the box.  You should use a guard on every
box because raccoons and climbing snakes can get up even thin metal poles
surprisingly easily.  

Conical and stovepipe guards are effective, but they can be expensive to
make and very expensive to buy.  








Hardware screen guards projecting out around the entrance hole are less
expensive, but they make it difficult and time-consuming for adult swallows
to access nests when feeding nestlings.  Note the overlarge hole and small
dimensions of the box below, obviously not a good design for Tree Swallows.








For additional information on predators and predator guards use this link to
Nestwatcher's Resource Center.

A simple and cheap alternative uses large juice or restaurant supply cans.  
The can ends are removed and its sides are cut in strips that are bent out.  
One cut goes all the way to the end so the can fits around a pole.  The guard
is supported by pieces of house construction "strap" secured to the pole by a
hose clamp.  But be careful handling these cans.  Their edges are sharp!








Two or three can guards fitted on a pole makes an effective predator barrier.


Why is grease sometimes put on poles?
Greasing the pole for 6-8 inches directly below a predator guard makes the
barrier even harder for predators to pass.
Pole grease is also keeps ants from reaching the nest.  







Note: If you decide to use can guards and grease, don't put them on right
away.  Most predation by mammals occurs at night.  However, male Tree
Swallows almost never roost overnight in boxes, and females usually don't
until they've begun to incubate their eggs.  If can guards or grease are added
before egg-laying swallows competing for boxes could be injured by the can
edges or get their feathers fouled by grease.  So, if you use can guards and
grease, wait until your females have begun incubating their eggs.  
                   
                                                         Top                           
Learn About Birds at Tree Swallow Nest Box Projects
Predator Protection