Individual study: Effect of heating nest boxes on egg laying in blue tits Parus caeruleus at Wytham Wood, Oxfordshire, England
Yom-Tov Y. & Wright J. (1993) Effect of heating nest boxes on egg laying in the blue tit (Parus caeruleus). The Auk, 110, 95-99
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Artificially incubate eggs or warm nests
A replicated, controlled trial in 1991 in woodland in Oxfordshire, England (Yom-Tov & Wright 1993), found that blue tits Parus caeruleus nesting in heated nest boxes did not have significantly heavier eggs or larger clutches than those in unheated boxes. However, birds were less likely to interrupt their laying sequence in heated boxes (33% of 16 heated nests had interruptions vs. 67% of 14 unheated nests). Heat was provided by a small ‘night light’ candle, 8 cm below the bottom of the box, which raised the temperature in the box by an average of 6oc, saving roosting blue tits approximately 0.77 kcal/night, comparable to 35% of the energetic cost of producing an egg.