Hands-On Field Projects

Req 5a — Nest Boxes

5a.

Construct, erect, and check regularly at least two artificial nest boxes (wood duck, bluebird, squirrel, etc.) and keep written records for one nesting season.

The Eastern bluebird nearly disappeared from most of the eastern United States by the 1970s — outcompeted for natural tree cavities by starlings and house sparrows that European settlers had introduced. What brought them back? Nest boxes. Thousands of volunteers installed millions of boxes along “bluebird trails,” and populations rebounded dramatically. What you’re about to do has a direct and documented track record of working. That’s not a metaphor — it’s measurable, repeatable conservation.

Why Nest Boxes Work

Many cavity-nesting birds — bluebirds, wood ducks, kestrels, tree swallows, screech-owls, nuthatches, and others — are limited by the availability of natural cavities in dead trees (called “snags”). As land development removes old trees and forests are managed more intensively, snags become scarce. Nest boxes substitute for natural cavities, and most species adopt them readily.

The key is making the right box for the right bird, placed in the right location. A wood duck box in an open meadow will never attract a wood duck. A bluebird box in a dense forest will never attract a bluebird. Matching species, box design, and habitat is what makes this project succeed.

Choosing Your Target Species

Your nest box plan should start with the question: what cavity-nesting wildlife lives in my area and needs nest boxes?

Bluebird (Eastern, Western, or Mountain): Open country, fence lines, meadow edges. Low nest entrance hole (1.5 inches) keeps starlings out. Mount on metal poles with predator guards.

Wood duck: Near water — wetlands, ponds, streams, flooded timber. Larger box (4" x 3" oval entrance) mounted on a metal pole in or at the water’s edge with a predator guard. Straw or wood shavings inside help ducks settle.

American kestrel: Open farmland, grasslands, forest edges. Medium-sized box (3" entrance hole) mounted 10–30 feet high on a post or tree.

Tree swallow: Similar habitat to bluebird — open fields and meadows near water. Accepts the same boxes. Often the first species to move in if bluebirds are slow to arrive.

Flying squirrel or gray squirrel: Woodland edges and forest interiors. Larger boxes (3" entrance) mounted 10–20 feet up a tree.

Screech-owl: Woodland edges, suburban trees, orchards. Medium box (3" hole) mounted 10–15 feet up in a tree or on a post.

Building Your Boxes

Use untreated, unpainted wood — cedar, pine, or fir work well. Never use pressure-treated lumber inside a box; the chemicals can harm eggs and nestlings. Key design features to include:

Ventilation holes near the top of the sides — 3/8-inch holes on each side keep the box from overheating
Drainage holes in the floor corners — water kills eggs and nestlings
Rough interior surface or horizontal grooves inside below the entrance — helps nestlings climb out
Sloped or overhanging roof — sheds rain away from the entrance
Side or front panel that opens — for monitoring and cleaning

Do not add a perch below the entrance hole. Perches help predators, not birds.

Placing Your Boxes

Location determines success. General principles:

Mount boxes at the height appropriate for your target species (see species list above)
Face entrances away from prevailing winds and direct afternoon sun (facing north or east is often best)
Space multiple boxes at least 100 feet apart for small species like bluebirds; wood ducks can be closer together since they don’t defend territories the same way
Install a predator guard (metal baffle or PVC sleeve on the mounting pole) — raccoons and snakes are effective nest predators

Write down the GPS coordinates or describe the exact location of each box. This is your first written record entry.

Monitoring Protocol

Check your boxes every 5–7 days throughout nesting season (April–July for most small birds; earlier for wood ducks). When you check:

Approach quietly; tap on the box before opening so adults can exit
Open the monitoring panel and record what you see (nest material present, eggs, nestlings, adults)
Don’t touch eggs or very young nestlings unless necessary
Close the box and move away quickly to minimize disturbance

After each nesting attempt (successful or failed), clean the box — remove old nest material so parasites don’t accumulate and so the pair or a new occupant can start fresh.

Nest Box Monitoring Log

What to Record

Your written records are the heart of this requirement. Record for each box visit:

Date and time
Weather conditions
Box number/location
Contents (empty, nest under construction, eggs — how many, nestlings — how many and estimated age, fledglings, abandoned)
Species (if identifiable)
Any evidence of predation or box damage
Any observations of adults at or near the box

At the end of the season, summarize: How many nesting attempts? How many eggs total? How many nestlings fledged? What problems did you encounter?

Keeping Peace Between Bluebirds and House Wrens — Nest Hollow

North American Bluebird Society — Nestbox Construction and Monitoring Detailed plans for multiple nestbox designs, monitoring protocols, and troubleshooting guides from the leading bluebird conservation organization in North America. NestWatch — Cornell Lab of Ornithology A citizen science nest monitoring program. You can register your nest boxes and submit your data — your observations become part of a national research database.

Be Prepared!

What If Nothing Uses Your Boxes?

Don’t panic if your boxes sit empty for weeks:

Check timing: Is it before nesting season? Bluebirds scout boxes early but may not start nesting until late March or April depending on your region.
Check placement: Is the habitat right for your target species? A box in dense woods won’t attract bluebirds.
Check for competitors: House sparrows and starlings may be evicting your target species. Remove house sparrow nests immediately — house sparrows are a non-native species and their nests are not legally protected. Starlings can be excluded by ensuring the entrance hole diameter is correct (1.5" for bluebirds excludes starlings but not house sparrows).
Be patient: It often takes two years for a box location to become established. Keep your records even if occupancy is low — “box not used” is a valid and useful data point.

Finished with your nest boxes? You can compare your approach to another option, or move ahead to the observation and research requirement.