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If I put up three nestboxes in my garden, will they all be occupied?

Sent in by Paul Howard, Leyland, Lancashire

The number of birds that can breed in an area depends on the available resources. A wildlife-friendly garden with plenty of nest sites and abundance of food would support more breeding birds.

Competition is most likely to occur between the blue tits and great tits. Both species prefer to nest in holes with clear flightpaths and have very similar diets.

Great tits will tend to dominate blue tits because they are larger. Ensure the nestbox for the blue tits only has a 25 mm hole so it will be unsuitable for a great tit. You can then provide a great tit nestbox with a 28 mm hole elsewhere. Putting the nestboxes as far apart as possible should help to avoid any conflicts. 

Mealworms can be a valuable food source in the breeding season. These can be put out to supplement the naturally occurring insects in your garden and should help reduce the competition.

Robins rarely show signs of aggression towards other species. They prefer to nest low down in dense vegetation in an open-fronted box, so would not compete with the tits for nest sites.

Reports of aggressive behaviour by robins towards other species are outnumbered by reports of robins actually feeding the young of other birds. They have very strong parental instincts and the sight of a baby bird gaping is too much for them to resist. Blackbirds, song thrushes, great tits and blue tits have all benefited.

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