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

Thaís Brisque,Augusto João Piratelli,Lucas Andrei Campos-Silva

doi:10.3897/zoologia.34.e13729

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 Muller, 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 long-term studies undertaken on their efficacy.

Highlights

Bird collisions with human structures are among the major anthropogenic causes of bird mortality in the world (Erickson et al 2005, Jenkins et al 2010, Rytwinski and Fahrig 2012, Calverti et al 2013, Loss et al 2014, DeVault 2015, Washburn et al 2015, Santos et al 2016)
What estimates exist are limited and they are largely extrapolations of data collected from a handful of locations in the Northern Hemisphere (Machtans et al 2013), often without considering the spatial variation of the urban landscape (Hager et al 2013)
Several studies in North America reported bird collisions with tall window-covered buildings numbering in the thousands over both the short- and long-term, even in a single day (Erickson et al 2005)

Summary

Introduction

Bird collisions with human structures (eg. vehicles, aircrafts, communication towers, wind turbines, power lines and buildings) are among the major anthropogenic causes of bird mortality in the world (Erickson et al 2005, Jenkins et al 2010, Rytwinski and Fahrig 2012, Calverti et al 2013, Loss et al 2014, DeVault 2015, Washburn et al 2015, Santos et al 2016). In North America alone, up to one billion birds are estimated to die due to collision with buildings (Loss et al 2014, Klem 2015). Human constructions with reflective glass are especially lethal, and have been considered one of the greatest causes of declines in global bird populations (but see Arnold and Zink 2011), second only to habitat loss (Klem 2006, 2009a). Several studies in North America reported bird collisions with tall window-covered buildings numbering in the thousands over both the short- and long-term, even in a single day (Erickson et al 2005)

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