A known unknown: elaboration of the observer effect' on nest success?

摘要

How often have young children found a bird’s nest and gazed at it in awe? Commonly, they marvel at not just the brightly coloured eggs of the Common Blackbird Turdus merula, for example, but also at the beauty of the nest structure itself (e.g. that of the Long-tailed Tit Aegithalos caudatus). For many this fascination with nests remains in adulthood and, indeed, for some of us it can shape the areas in which we choose to focus our research efforts. The mesmeric properties of nests transcend both professional and amateur circles of ornithology. This is evidenced by the 4000 nests held in a research collection of the Natural History Museum in Tring, Hertfordshire, UK, and by the success of the British Trust for Ornithology’s (BTO’s) Nest Record Scheme, which every spring and summer engages approximately 500 volunteer nest recorders visiting approximately 30 000 nests of many different species.