Use of RFID technology to characterize feeder visitations and contact network of hummingbirds in urban habitats

Abstract

Despite the popular use of hummingbird feeders, there are limited studies evaluating the effects of congregation, sharing food resources and increased contact when hummingbirds visit feeders in urban landscapes. To evaluate behavioral interactions occurring at feeders, we tagged 230 individuals of two species, Anna’s and Allen’s Hummingbirds, with passive integrated transponder tags and recorded their visits with RFID transceivers at feeders. For detecting the presence of tagged birds, we developed an RFID equipped feeding station using a commercially available antenna and RFID transceiver. Data recorded included the number of feeder visits, time spent at the feeder, simultaneous feeder visitation by different individuals, and identifying which feeders were most commonly visited by tagged birds. For the study period (September 2016 to March 2018), 118,017 detections were recorded at seven feeding stations located at three California sites. The rate of tagged birds returning to RFID equipped feeders at least once was 61.3% (141/230 birds). Females stayed at feeders longer than males per visit. We identified primary, secondary and tertiary feeders at Sites 2 and 3, according to the frequency of visitation to them, with a mean percentage of 86.9% (SD±19.13) visits to a primary feeder for each tagged hummingbird. During spring and summer, hummingbirds visited feeders most often in morning and evening hours. Feeder visits by males overlapped in time with other males more frequently than other females. The analysis of the contact network at the feeders did not distinguish any significant differences between age or sex. Although most hummingbirds visited the feeders during the daytime, our system recorded night feeder visitations (n = 7 hummingbirds) at one site. This efficient use of RFID technology to characterize feeder visitations and contact networks of hummingbirds in urban habitats could be used in the future to elucidate behaviors, population dynamics and community structure of hummingbirds visiting feeders.

Anti-microbial activity of whole blood and plasma collected from Anna’s Hummingbirds (Calypte anna) against three different microbes

“…When at feeders, hummingbirds interact with an average of seven other birds. Male to male interactions tend to happen most frequently followed by male to female interactions and female to female interactions [27]. Our data indicate male Anna's hummingbirds have higher anti-microbial activity than females.…”

Pairing automated mark–recapture and social network models to explore the effects of landscape configuration on hummingbird foraging patterns

“…We highlight the value of pairing an underutilized passive mark-recapture approach with social network models in the study of foraging patterns of small-bodied organisms (see also [13,18]). We aimed to gain insight into the functional connectivity of high-elevation meadows in the Cascade Mountains in the face of forest encroachment by investigating foraging behaviours of a common pollinator, rufous hummingbirds, in the current landscape.…”

“…These methods offer multiple benefits. First, our methods employ passive mark-recapture techniques which may yield large volumes of data with reduced labour cost [13]. Second, sender-receiver models allow us to estimate the effects of landscape features on the connectivity of fixed locations in a generalized regression framework and allow insight into movement patterns such as the reciprocity of movements which may elucidate sourcesink dynamics (emigration out of high-density areas with minimal immigration) and directional gene flow.…”

Retrospective study on admission trends of Californian hummingbirds found in urban habitats (1991–2016)

“…Commonly found in urban settings due to the use of man-made feeders, hummingbirds are key pollinator species in urbanized areas ( Maruyama et al, 2019 ). Hummingbird distribution ( Greig, Wood & Bonter, 2017 ), population composition, and intra- and inter species interactions ( Bandivadekar et al, 2018 ; Carpenter, 1987 ; Ditchkoff, Saalfeld & Gibson, 2006 ; Lowry, Lill & Wong, 2013 ; Ng et al, 2004 ; Thomas, Baker & Fellowes, 2014 ) all have been significantly affected due to increased artificial food-resource provisioning, and urbanization. Empirical studies describing disease and health risks in hummingbirds found in urban habitats are still needed.…”