Relationship between bird-of-prey decals and bird-window collisions on a Brazilian university campus

Abstract

ABSTRACT. Bird-window collisions are a dramatic cause of bird mortality globally. In Latin America, statistics are generally very scarce and/or inaccessible so the frequency of such incidents is still poorly understood. Nevertheless, civilians have applied preventive methods (e.g. adhesive bird-of-prey decals) sparsely but, to our knowledge, no study has evaluated their effectiveness in Brazil. Here, we estimated the mortality rate of bird-window collisions and tested the effectiveness of bird-of-prey decals at preventing such accidents. We undertook daily searches for bird carcasses, presumably resulting from window collisions, near all buildings on a university campus over seven months. Adhesive bird-of-prey decals were then applied to the two buildings with the highest mortality rates and surveys continued for over 12 more months. The mortality rates before and after the application of decals and between seasons were then compared using Friedman test. We recorded 36 collisions, 29 around the two buildings with the highest collision rates 19 prior and 10 after our intervention with associated collision rates of 0.08 and 0.04 collisions/day. Although mortality was reduced by almost half, this difference was not statistically significant. The Blue-black grassquit, Volatinia jacarina (Linnaeus, 1766), and Ruddy ground dove, Columbina talpacoti (Temminck, 1810) suffered the highest number of collisions, followed by the Rufous-collared sparrow, Zonotrichia capensis (P. L. Statius Müller, 1776). Our bird-of-prey decals and efforts were insufficient to prevent or dramatically reduce the number of bird-window collisions. Therefore, we recommend that different interventions be used and additional longterm studies undertaken on their efficacy.

Main causes of bird-window collisions: a review

“…There is a clear imbalance in the scientific production and, therefore, in the knowledge of bird-window collisions. Most studies are from the Northern Hemisphere, while information from the Southern Hemisphere is still scarce (but see Ocampo-Peñuela et al 2016, Brisque et al 2017, Santos et al 2017. This is worrying because most of the world's bird species reside in tropical countries (Myers et al 2000), and many can be decreasing partly due to collisions with human structures.…”

“…There is no consensus on the effect of local weather conditions on collisions (e.g. Cousins et al 2012, Hager et al 2012, Ocampo-Peñuela et al 2016, Brisque et al 2017.…”

“…The environmental characteristics and anthropogenic influences also widely vary (e.g. Klem 1990b, Rössler et al 2015 and the solutions may not always be applicable (Brisque et al 2017). Environmental factors and their attractiveness to birds can influence bird abundance, thus increasing their vulnerability to collisions (Hager et al 2008, 2013, Cusa et al 2015.…”

“…The number of scientific studies is therefore still limited (Santiago-Alarcon & Delgado-V 2017, but see Seewagen & Sheppard 2018), mainly in tropical regions, where only a few local studies are known (e.g. Agudelo-Álvarez et al 2010, Brisque et al 2017, Santos et al 2017). An update on existing data is required, aiming to identify collision patterns, to fill in knowledge gaps and identify the most threatening scenarios.…”

Ecology, endemism, and conservation status of birds that collide with glass windows in Monteverde, Costa Rica

“…While many studies document bird collisions in the United States and Canada, relatively few studies have taken place in the Neotropics; these include studies from Colombia (Agudelo-Álvarez, 2006;Agudelo-Álvarez, Moreno-Velasques, & Ocampo-Peñuela, 2010;Ocampo-Peñuela et al, 2016), Costa Rica (Graham, 1997;Menacho-Odio, 2015;Oviedo & Menacho-Odio, 2015), Mexico (Cupul-Magaña, 2003;Gómez-Moreno, Herrera-Herrera, & Niño-Maldonado, 2018), and Brazil (Briske, Campos-Silva, & Piratelli, 2017;Santos, Ferreira, & Ferreira, 2017). Studies conducted in Important Bird Areas (IBA) are even more infrequent (Santos et al, 2017).…”