Nest-boxes for Common Swifts Apus apus as compensatory measures in the context of building renovation: efficacy and predictors of occupancy

Abstract

SummaryCurrently, renovation and thermal insulation of buildings is happening at a high rate in many European countries, driven in part by the political aim to reduce greenhouse gas emissions. Unfortunately, building renovations often lead to a loss of structures, such as accessible cavities, on which synanthropic species, for example house-nesting birds, depend. In Germany, due to legislative regulations, it is a common practice to install nest-boxes as compensation for destroyed nest sites of birds. However, studies on the efficacy of such measures remain sparse. We monitored the occupancy of 477 compensatory nest-boxes for Common Swifts Apus apus, predominantly placed on renovated prefabricated buildings in a city in Germany. We found 24.3% of the boxes occupied by Swifts. On most buildings, the number of occupied boxes was as high as or even higher than the assumed number of breeding sites prior to renovation. Furthermore, in a district where nearly all buildings had been renovated in the past 10 years, we recorded a remarkably high density of Swifts breeding in nest-boxes. Using boosted regression trees, we analysed whether eight different nest-box properties influenced box occupation probability. The number of neighbouring boxes was the most important. Additionally, box age, facade orientation, city district, relative and absolute height, and manner of installation (external/internal) also played a role. Between different nest-box types, we found only negligible differences in occupation probability. Our findings suggest that installing nest-boxes is likely to be an appropriate measure to compensate for nesting sites of Swifts lost during building renovations. Based on our results, we recommend mounting the boxes a few metres apart from each other and close to the roof edge to maximise success. Further studies should be carried out to assess whether our results and conclusions can be confirmed in other situations.

Urbanisation and nest building in birds: a review of threats and opportunities

“…Nestboxes, artificial platforms and even artificial burrows are widely provided for birds such as passerines (Passeriformes) (e.g., Remacha and Delgado 2009;Schaub et al 2015;Reynolds et al 2016;Duckworth et al 2017;Lambrechts et al 2017; Fig. 1a), storks (Ciconiiformes) (e.g., Tryjanowski et al 2009), raptors (Falconiformes) (e.g., Postupalsky and Stackpole 1974;Tigner et al 1996;Fig.…”

“…1a), storks (Ciconiiformes) (e.g., Tryjanowski et al 2009), raptors (Falconiformes) (e.g., Postupalsky and Stackpole 1974;Tigner et al 1996;Fig. 1b), owls (Strigiformes) (e.g., Smith et al 2005) and swifts (Apodiformes) (e.g., Schaub et al 2015) within urban landscapes. Whilst at first sight nestboxes provided by individual householders may appear to provide few nesting opportunities for urban birds, nestboxes can be highly abundant in some urban areas.…”

“…The availability of different kinds of nestboxes may increase the colonisation of urban parks by a great variety of cavity-nesters, including threatened species (Jokimäki 1999;Jokimäki et al 2018). Nestboxes increase breeding opportunities for urban birds, because there are fewer natural cavities or hollows in trees in urban areas than in continuous woodlands (Davis et al 2014b); they ensure that nest sites are available in areas where they would otherwise be limiting (Schaub et al 2015). They can, however, also be disadvantageous by acting as ecological traps (Demeyrier et al 2016) or by being occupied by a variety of invasive species of birds (Grarock et al 2013;Bender et al 2016) and mammals (Harper et al 2005).…”

“…If a species is able to exploit opportunities such as holes and cavities in buildings for nesting while tolerating human presence, this may facilitate population growth and establishment in the novel breeding niches in cities (see review by Tomiałojć 2016). Authors including Schaub et al (2015) suggest that modern building design should accommodate the breeding requirements of cavitynesting species. Additionally, creation and management of urban green spaces should include retention of old trees, providing cavities and/or provision of nestboxes to support breeding attempts of threatened, cavity-nesting species such as Orange-bellied Parrots in Australia (Loyn et al 1986).…”

Light data from geolocation reveal patterns of nest visit frequency and suitable conditions for efficient nest site monitoring in Common SwiftsApus apus

“…In some countries (e.g. Germany), Swift nest sites are protected by nature conservation laws and must be preserved during renovation works and/or replaced by compensatory measures (nest-boxes; Schaub et al 2016). Owing to the inaccessibility of Swift nest sites, these normally need to be identified by watching the building's facade from the ground.…”