Set‐Back Distances to Protect Nesting Bird Colonies from Human Disturbance in Florida

Abstract

Breeding colonial waterbirds are particularly susceptible to human disturbance because of their high-density nesting habtt~ Identified detriments to reproductive success include egg and nestling mortality, nest evao~tior~ reduced nestling body mass and slower growth, premature fledging and modified adult behaviorg Fifteen species of colonial waterbtrds nesttng at 17 colonies in north and central Florida were exposed to three different human disturbance mechanisms (HDMs) in order to determine recommended set-back (RS) distances for protecting these mixed-species nesting assemblage~ Both intraspeciflc and inter. specific variation were observed in flushing response distances to the same human disturbance mechani.¢mg In genera~ colonial waterbirds exhibited greater average flush distances in reaction to a walking approach than to approaching motor boat~ Recommended set-back distances were estimated using a formula based on the mean plus 1.6495 standard deviations of the observed flushing distances plus 40 meters ~S = exp (# + 1.64950 + 40)]. In genera~ a recommended set-back distance of about 100 meters for wading bird colonies and 180 meters for mixed tern~skimmer colonies should be adequate to effectively buffer the sites we studied from human disturbance caused by approach of pedestrians and motor boats. We recommend follow-up studies to test our model at other breeding colonies.Distancia de alejamiento para proteger de las perturbaciones humanas alas colonias de aves nidificadoras en Florida Resumen: Las ayes acu~ticas que habitan en colonias durante el pertodo de criag son particularmente susceptibles alas perturbaciones humanas por sus hdbitos conducentes a una alta demidad de nido~ Los factore$ que disrainuyen el dxito reproductivo, tncluyen ia mortaltdad del huevo y el ptch6r 6 la evacuaci6n del nid~ la reducci6n de la masa corporal del pich6n o crecimeiento lento, el abandono prematuro del ntdo por parte de los pie.hones y comportamtentos adultos modificados Quince especies de colonias de ave$ acu~ticas que nidtflcaron en 17 colontas del norte y centro de Floridg fueron expuestas a 3 mecanismos de perturbaci6n humana dtferenteg a los efectos de deterrainar distanctas de alejamtento recomendables para proteger las agregaciones mtxtas de dstas especie£ Variactones tntra-especificas e inter-especificas en ias distanctas de respuesta frente a los mismos mecanismos de perturbaci6n humana En genera~ los colonias de ayes acu~ttcas exhtbteron una mayor dtstancia promedio antes de volar en reacct6n a la cercania de pasos que al acercamiento de una embareactbn a motor. La dgstancia recomendada de alejamiento rue esttmada utilizando una f6rmul~ basada en la media md~ 1.6495 desvtaciones standard de la distancias antes de volar observad~ md$ 40 m ~RS = exp (# + 1. 64958 + 40)]. En genera~ una distancia de alejamiento de alrededor de 100 m para lus colontas de aves zancudas y 180 m para las colonias mtxtas ("tern/skimmer"), seria adecuada para amortiguar a los sitios que estudiamos de los tmpactos de las perturbaciones ...

Responses of Birds to Humans at a Coastal Barrier Beach: Napatree Point, Rhode Island

“…Estimates of FID have significant ramifications for management of shorebird and waterbird breeding and stopover habitat , Koch and Paton 2014, Rodgers and Smith 1995, Weston et al 2012a). The median FID we documented when birds were disturbed by walkers or boats (~40 m) is similar to distances reported in previous studies (e.g., Blumstein 2003, Burger and Gochfeld 1991, Thomas et al 2003, but less than values reported for some larger species of shorebirds documented in other areas (e.g., Koch and Paton 2014), perhaps due to different methods of observation and analysis between studies.…”

“…The median FID we documented when birds were disturbed by walkers or boats (~40 m) is similar to distances reported in previous studies (e.g., Blumstein 2003, Burger and Gochfeld 1991, Thomas et al 2003, but less than values reported for some larger species of shorebirds documented in other areas (e.g., Koch and Paton 2014), perhaps due to different methods of observation and analysis between studies. The disturbancedensity map we developed provides guidance for Napatree Point resource managers on possible regions from which pedestrians and boats should be excluded during migration periods and breeding season in order to reduce disturbance to birds (Ikuta andBlumstein 2003, Rodgers andSmith 1995).…”

“…To develop a spatially-explicit management zone to protect nesting, foraging, and roosting shorebirds and waterbirds at Napatree Point, we extracted the top 50% (i.e., greater than the median disturbance density) of areas in the disturbance-density map to determine where most disturbance events took place. By buffering this area by 40 m, the recommended additional buffer by Rodgers and Smith (1995), we established a management zone where pedestrians and watercraft were likely to intrude in the highest disturbance-density area (Fig. 2).…”

Forest management and stick-nesting birds: New direction for mitigation in Ontario

“…Given this scarcity of information, buffers were developed to mitigate the effects of human disturbance based on the distance birds were expected to flush (fly) from their nests when approached by pedestrians (see Holmes et al 1993, Rodgers and Smith 1995, and Swarthout and Steidl 2001 for examples of previous use of this approach). Flushing of nesting birds by humans is considered potentially detrimental to reproductive output because flushing birds may attract nest predators or the absence of parent birds may render eggs or young vulnerable to predators or environmental stress.…”

“…Estimated flushing distance represents the expected mean for each species, so using this value to define a buffer might only protect 50% of nests. To identify the buffer size needed to protect 95% of nests, mean flushing distance was multiplied by 1.6495 standard deviations and then increased by 40 m (to account for the distance birds may become agitated prior to flushing) following the method used by Rodgers and Smith (1995). The relationship in Fig.…”