Nesting boxes are a source of new life and bring much joy to bird lovers. Given enough free time to watch, you could see the birds gathering material to line the box, the female staying in to incubate the eggs and the male tirelessly foraging for food to feed the hen and their chicks. Your greatest reward will be seeing a group of fledglings learning to fly and fend for themselves.
But not everything about a bird box is good news; did you know that left dirty, they can spread disease to any future inhabitants?
If you were wondering if and when should you clean out bird boxes, here’s your definitive guide.
There are two primary reasons for cleaning out used bird boxes;
- Future inhabitants will probably be put off from using the box if the remnants of a previous brood remain
- Any birds that do reuse the nesting box may become ill, especially susceptible chicks. Mites, fleas, and parasites linger in the dirty nest and will infect new residents.
When to clean out a bird box
Always wait until the end of the breeding season, ensure the box is empty and all the birds have flown.
Different species fledge at different times of the year, but the last residents have usually left by September; I think waiting until October is best to be on the safe side.
Don’t be surprised to find eggs in the nest at this time of year; they won’t hatch now; the nest was abandoned. Adults desert nests should one of them die or if the nest has been interfered with by predators, animals or humans. If the temperature is too cold to bear, or if food is scarce, birds might also abandon their clutch of eggs.
In England, it is legal to remove and dispose of these eggs between September and January in Scotland, it is August – January.
How to clean out a bird box
Open up the roof on the box and remove any remnants of the nest; I always wear gloves to do this job. Tie it securely in a plastic bag – it may have fleas inside – and dispose of it.
I use an old knife to scrape out droppings, again, dispose of them safely.
Many people prefer to use plain boiling water to wash the box; I use very weak bleach solution. It is at least 1-part bleach to 30+ parts water. I feel it leaves the box well-sanitized.
Use an old toothbrush to scrub every nook and cranny before rinsing soundly with boiling water.
Leave the box to dry thoroughly before reattaching the roof. Any damp will encourage mould growth that can prove fatal to birds.
When to hang your bird box out
Birds begin to look for nesting sites as early as January; most have usually chosen their space by the start of spring. Some people choose to hang their boxes then.
I return mine to the tree as soon as they have dried. Lots of birds (and some small mammals) make use of empty bird boxes to shelter through winter. Without nesting boxes, some species might perish when temperatures drop.
Wrens make good use of them when it is cold; they gather in huge numbers, as many as 20 birds roost overnight in a single box. Their body heat keeps each other warm.
In my opinion, if it’s possible, you should always clean out bird boxes when you’re sure all of the inhabitants have left.
They will be more inviting to our feathered friends, smell better, and be a safer environment to raise young.