Old Nest Material in Nest Boxes of Tree Swallows: Effects on Nest-Site Choice and Nest Building

Abstract

ABSTR•CT.-In natural cavities, old nest material accumulates with successive use, thereby reducing the size of the cavity, and allowing the numbers of certain haematophagous ectoparasites to increase. For this reason and because researchers studying birds breeding in nest boxes typically remove old nests from boxes, the results of such studies have been questioned. The accumulation of old nest material might affect nest-site selection and nest building by hole-nesting birds, so we tested this hypothesis by manipulating the presence and amount of old nest material in nest boxes of Tree Swallows (Tachycineta bicolor). Our experiment also allowed us to examine whether costs are incurred by females due to nest building in terms of their subsequent reproductive output. When a choice of boxes was available, swallows preferred empty and clean boxes, or those where the old material had been microwaved, over those with old, untouched material. Clean boxes and those with microwaved material had more space inside, so our experiments support two hypotheses: swallows avoid potentially high numbers of parasites in nests with old material; or they prefer large cavities. Empty boxes affected nest building. The mass and volume of nests built in clean boxes were greater than for nests built on old material. Females did not add more feathers to the nest lining in boxes with old material as compared with clean boxes. Correlation analyses suggested that females building large nests began egg laying earlier in both years. Otherwise, there were no associations between the sizes of nests built by females and subsequent reproductive output (e.g. clutch size) or nestling size (e.g. body-condition index). Our results show that the common habit of removing old nests from boxes can affect nest-site choice and nestbuilding behavior. Nest building does not influence reproductive output by Tree Swallows.

Effect of Old Nest Material on Nest Site Selection and Breeding Parameters in Secondary Hole Nesters — a Review

“…increased ectoparasite and predator pressure, was not high, or was even decreased by the experimental procedures used. In studies where old nests were heat-treated, birds were found avoiding ectoparasites, and not the nest material itself (Oppliger et al 1994, Rendell & Verbeek 1996b, but Orell et al 1993). However, several other studies demonstrated that ectoparasite abundance did not differ between nests built in sites with or without an old nest (Table 4).…”

“…In the European Starling, for whom an avoidance of sites with old nest material was found in similar experiments, an additional experiment controlling for nest site depth revealed no preferences in relation to presence of old nests (Mazgajski 2003). Two similar types of experiments were carried out on Tree Swallows, but only the results of the first were presented, when nest site depth was not taken into consideration (Rendell & Verbeek 1996b Table 2. Effect of old nest material on nest site choice of hole nesting bird species.…”

“…In Tree Swallows as well as in Blue Tit, it was found that choosing nest sites with or without old nests was not related to the age of females, which could be connected with intraspecific competition (Rendell & Verbeek 1996b, Tomás et al 2007), although for the Purple Martin, Hill (after Brown 1997) suggested that older females may prefer nest sites with old nests, which could be related to fidelity for their own previous nest sites.…”

“…Four papers were found reporting results of experiments that determined if birds' preferences for nest sites are connected with the presence of an old nest itself or the ectoparasites occurring in them (Orell et al 1993, Oppliger et al 1994, Olsson & Allander 1995, Rendell & Verbeek 1996b. In those experiments, the old nest material was heated to kill all ectoparasites and/or old nests were infected by a defined number of fleas (Siphonaptera).…”

“…Nestboxes containing Pied Flycatchers' old nests were more frequently used even with the additional increase of fleas in comparison with nestboxes cleaned by investigators before the breeding season (Orell et al 1993, Olsson & Allander 1995. On the other hand, it was found that Tree Swallows preferred those nestboxes where old nest material was heat-treated (Rendell & Verbeek 1996b). Data on the Great Tit are also contradictory.…”