These kinds of birds require a cavity, or chamber, to safely and successfully raise their young every year -- that either they excavate themselves (primary cavity nesters like woodpeckers and sapsuckers) or one they can find which was made by somebody else (secondary nesters like kestrels and bluebirds). Belted kingfishers are also primary cavity nesters but their cavity is actually a long, narrow tunnel burrowed into a soft dirt exposed river cut bank, sandy cliff or large dune.

Nationwide, landowners have been advised to remove dead trees called snags or old trees that have decay for safety and fire prevention purposes. Where people commonly walk and near buildings, this advice makes sense but may be overkill in less travelled or remote areas. In these more remote areas, punky snags provide easy-to-excavate and sometimes insect stuffed trees for primary cavity nesters.  

As more areas get developed, there is concern that many bird populations may be declining because they can’t find a safe cavity to raise their young. Even though we can still commonly see kestrels and bluebirds (both western and mountain varieties) in the White Mountains, more widespread evidence appears to be pointing to declines in their numbers. This information inspired the formation of programs to make nest cavities from boxes and monitor their use for both kestrels and bluebirds. 

Kestrels, also known as sparrow hawks, are the smallest member of the falcon family in Arizona and are undeniably the most colorful and easy to observe. Males have an obvious rusty brown back, slate blue head and wings and two distinctive facial stripes, along with black spotted underparts and no bands on the tail. Females have the eye stripes and brown streaked breast, but are a more camouflage brown on the topside and wings and have fine dark bands on the tail. Other Arizona falcons include the prairie and peregrine falcons, as well as merlins and maybe an occasional Aplomado falcon in extreme southern Arizona. 

Kestrels primarily eat insects, rodents, small rodent pests and birds and prefer more open habitats like grasslands, large meadows and pinyon juniper expanses. They can often be seen perched alongside roads on wires and posts or hovering in place before they fold their wings to drop and catch prey. You might see fewer of them during the winter, as some may migrate to warmer climes, but they are usually seen year-round in the open habitats. A healthy kestrel population can put a dent in pest rodent populations and they don’t even use expensive toxic chemicals or charge for their services. What a deal!

Citizens are invited to participate in a project to study kestrel populations in Arizona. The Game and Fish Department is cooperating with the Peregrine Fund to sponsor the American Kestrel Partnership project by building a network of citizen scientists to build, place and monitor nest boxes. Participants can build or purchase their own boxes and, with direction provided by a local Game and Fish biologist, place, monitor and maintain the boxes. Monitoring will involve climbing a ladder to look into the boxes at least a couple times during the breeding season to document egg production and fledgling or free flying of the young.  

Citizen naturalists will also need to clean out the boxes every winter and replace the bedding material as well as report the use or non-use of their boxes, either online or to the local biologist. Following the growth of a kestrel family -- including observing them catching enough food to feed a growing nest of voracious chicks -- can be an entertaining pastime. And it can be done from the comfort of your vehicle with a pair of binoculars or a spotting scope mounted on your half-way-rolled-down side window. Kestrels are not as wary as other falcons and can tolerate observers at a safe distance.  

Both species of bluebirds eat insects and resort to berries and fruit when bugs are not available. So, that means they have to migrate during the coldest and snowiest parts of our winters and can be found at lower elevations in grasslands and pinyon juniper forests. During the summer, they both can be found overlapping in most areas but the mountain bluebird dominates in the highest elevations. Upon their spring return, the males allow the females to choose the nest cavity -- which is usually the one they used the previous year if it hasn’t been taken over by a more aggressive bird like a starling or cowbird.

Citizen naturalists can also help bluebird populations by building or buying bluebird houses, erecting them in suitable habitat, monitoring their use and cleaning them out after the breeding season in preparation for next year. Bluebird trails -- or a collection of houses distributed along a road, trail or fence line -- are an effective and efficient method to provide many pairs of bluebirds nice homes in an arrangement that makes it easy to monitor and maintain the boxes. The boxes should be made to specific dimensions, like kestrel boxes, to have the best chance of use by the birds. If boxes are not made according to instructions found on the many helpful internet sites (see below), they may not be used and, if they are, they could allow predators to prey on the youngsters. 

Mounting the bluebird houses on fence posts or within view of a road allows you to monitor them for use from within your vehicle with the right optics. However, you will need to actually visit the boxes regularly to check for problems like ants, leaky roofs, invasion by non-native starlings and house sparrows or cowbirds who lay their own eggs in the nest for the bluebirds to raise for them, When you sign up to become involved with nest box monitoring, you will be provided with plenty of instructions and help to get you started, including house plans, monitoring instructions and data forms.