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It is assumed that many birds attempt to conceal their nests by using camouflage. To our knowledge, however, no previous experimental studies have explicitly tested this assumption. To explore whether birds choose materials that match the background colors of nest sites to reduce the conspicuousness of their nests, we offered nest-building male Zebra Finches (Taeniopygia guttata) a choice of nest materials that either matched or did not match the color of their nest cup and the surrounding cage walls. Males chose to nest predominantly with material that matched the background color of the cage. To our knowledge, this is the first experimental evidence that birds actively select materials that camouflage their nests. [ABSTRACT FROM AUTHOR]

Across the animal kingdom, many animals build structures. One especially diverse example is that of nest building by birds. It remains unclear, however, what birds know or whether they learn about the structural aspects of the material with which they build a nest. Here we tested whether nest-building male zebra finches would choose the appropriate type of material when building in a novel situation. They did do this: males provided with a nestbox with either a small or a large entrance hole and with nest material of two types (‘long’ and ‘short’) chose the type of material that was appropriate for the box in which they built. Additionally, the birds' material use improved with experience: males building in nestboxes with small entrances became less choosy in their material choice as they became more skilled at inserting material of either length into their nestbox. The birds, therefore, first chose the appropriate materials for the nestbox in which they were building but then modified their handling skills so as to make use of all of the available material. How the cognitive abilities used in this nest-building context compare with those used in solving other physical problems such as tool use tasks is not yet clear. [Copyright &y& Elsevier]

Highlights: [•] It is not always clear why nest-building birds choose the materials they do. [•] We compared nest and food colour preferences in male zebra finches. [•] Birds preferred blue nest material, but had no food colour preferences. [•] It appears that nest material colour preferences are specific to that context. [Copyright &y& Elsevier]

Nests are built by nearly all bird species and can be extremely varied in their structural characteristics, both within and among species. As with a number of other avian behaviours, it seems plausible that early learning might be important in producing adult nest-building behaviour. To examine whether preferences that adults have for nest materials are related to their early-life experience, we experimentally manipulated the colour of the nest in which Zebra Finch pairs built and raised chicks. We then tested these chicks at maturity to determine whether they preferred the colour of the nest from which they had fledged or preferred the same colour as their father. We also examined the overall structure of nests that fathers and their sons built to determine whether the nest a male builds resembles that from which he hatched. When males and females naïve to building were paired as adults and tested for their nest material preferences, they did not prefer the colour of their natal nest. When these males were re-paired and their preference tested a second time, the majority then preferred the colour that their father had preferred (which was also the colour preferred by most of the males). The structural components of a male's nest did not resemble the nest built by his father, but neither did his father's nests resemble each other. We found no evidence that the experience of the nest from which a bird fledges influences his preferences for the colour of nest material or the structure of his first nest. [ABSTRACT FROM AUTHOR]

Whether learning plays a role in nest building in birds is largely unknown. Here we investigated whether the colour of nest materials used to build a first nest affected the subsequent nest material choices made by male zebra finches when building a second nest. Males were tested for their preference for green or brown nest material and then were provided with either their preferred or nonpreferred colour with which to build their first nest. The success of this nesting attempt was manipulated such that half of the breeding pairs had their eggs removed, while the other half were allowed to keep their eggs and fledge chicks. Males were then retested to determine which colour of nest material they now preferred. Males had strong initial preferences for one or other of the two colours of nest material. Males that built a nest with their preferred colour of nest material continued to prefer that colour after nesting, regardless of their breeding success in that nest. However, of the males that built a nest with material of their nonpreferred colour, those that raised and fledged chicks from it subsequently preferred that colour of material for their second nest, while males that suffered a failed breeding attempt did not. Thus breeding experience can influence decisions relating to nest material choice in nest construction in the zebra finch. [Copyright &y& Elsevier]