
Orr SpiegelTel Aviv University | TAU · School of Zoology
Orr Spiegel
Professor
About
107
Publications
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Introduction
I'm a faculty member at the School of Zoology, Tel Aviv University. I work on behavioral and movement ecology. Please visit my lab's homepage at https://orrspiegel.wixsite.com/orrspiegel
Cheers,
Orr
Additional affiliations
July 2018 - August 2019
August 2018 - present
September 2013 - present
Publications
Publications (107)
Fleshy-fruited plants are usually dispersed by an array of frugivores, differing in the effectiveness of the dispersal service they provide to the plant. Body size differences among frugivores are hypothesized to affect seed dispersal distances and consequently their effectiveness as dispersers. We tested this hypothesis by comparing the effectiven...
Animal movements exhibit an almost universal pattern of fat-tailed step-size distributions, mixing short and very long steps. The Lévy flight foraging hypothesis (LFFH) suggests a single optimal food search strategy to explain this pattern, yet mixed movement distributions are biologically more plausible and often convincingly fit movement data. To...
Understanding how animals interact with their physical and social environment is a major question in ecology, but separating between these factors is often challenging. Observed interaction rates may reflect social behaviour – preferences or avoidance of conspecifics or certain phenotypes. Yet, environmental spatiotemporal heterogeneity also affect...
Recent studies have established the ecological and evolutionary importance of animal personalities. Individual differences in movement and space-use, fundamental to many personality traits (e.g. activity, boldness and exploratory behaviour) have been documented across many species and contexts, for instance personality-dependent dispersal syndromes...
When individual animals make decisions, they routinely use information produced intentionally or unintentionally by other individuals. Despite its prevalence and established fitness consequences, the effects of such social information on ecological dynamics remain poorly understood. Here, we synthesize results from ecology, evolutionary biology, an...
Host personality can markedly affect parasite transmission. Especially for parasites with indirect transmission through the environment, the effects of consistent among‐individual differences in behavior may have both direct and indirect components. For example, personality may mediate both how hosts respond to infected individuals and the likeliho...
The transmission of zoonotic diseases between animals and humans poses an increasing threat. Rabies is a prominent example with various instances globally, facilitated by a surplus of meso-predators (commonly, facultative synanthropic species e.g., golden jackals [Canis aureus, hereafter jackals]) thanks to the abundance of anthropogenic resources...
The installation of automatic detection systems (ADSs) on operating wind energy facilities is a mitigation measure to reduce bird collisions. The effectiveness of an ADS depends on a combination of parameters, including the detection distance of the bird, its flight speed, and the time to complete the chosen action (e.g., turbine shutdown). We crea...
Understanding how wildlife responds to the spread of human-dominated habitats is a major challenge in ecology. It is still poorly understood how urban areas affect wildlife space-use patterns and consistent intra-specific behavioural differences (i.e. behavioural types; BTs), which in turn shape various ecological processes. To address these questi...
Uncovering the ways in which pathogens spread has important implications for population health and management. Pathogen transmission is influenced by various factors, including patterns of social interactions and shared use of space. We aim to understand how the social behaviour of griffon vultures (Gyps fulvus), a species of conservation interest,...
The behavioral characteristics of species may result in certain populations being inherently more susceptible to fragmentation. For example, species exhibiting spatial sexual segregation or those constrained to elongated and narrow habitats. We studied the fragmentation threats, spatial dynamics, resource utilization, and movement ecology of a part...
Animal movement plays a key role in many ecological processes and has a direct influence on an individual’s fitness at several scales of analysis (i.e., next-step, subdiel, day-by-day, seasonal). This highlights the need to dissect movement behavior at different spatio-temporal scales and develop hierarchical movement tools for generating realistic...
Studying the spatial–social interface requires tools that distinguish between social and spatial drivers of interactions. Testing hypotheses about the factors determining animal interactions often involves comparing observed interactions with reference or ‘null’ models. One approach to accounting for spatial drivers of social interactions in refere...
Studying the mechanisms shaping age-related changes in behavior ("behavioral aging") is important for understanding population dynamics in our changing world. Yet, studies that capture within-individual behavioral changes in wild populations of long-lived animals are still scarce. Here, we used a 15-y GPS-tracking dataset of a social obligate scave...
Given the current biodiversity crisis, understanding how animals move across a landscape dotted with different anthropogenic threats and the consequences of those threats for animals is paramount to devising evidence‐based conservation interventions. Vultures roam across large areas and are highly exposed to poisoning, which represents a particular...
Improved animal tracking technologies provide opportunities for novel segmentation of movement tracks/paths into behavioral activity modes (BAMs) critical to understanding the ecology of individuals and the functioning of ecosystems. Current BAM segmentation includes biological change point analyses and hidden Markov models. Here we use an elementa...
Mycoplasmas are known as commensals and pathogenic bacteria of various raptor species causing clinical or subclinical infections. However, little is known about the prevalence of mycoplasma in captive and wild raptors and its significance to their health. In Israel, the Griffon vulture ( Gyps fulvus ; hereafter Griffons) is considered critically en...
High population density should drive individuals to more frequently share space and interact, producing better-connected spatial and social networks. Despite this widely-held assumption, it remains unconfirmed how local density generally drives individuals' positions within wild animal networks. We analysed 34 datasets of simultaneous spatial and s...
Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual's behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT‐dependent effects across multiple stages of the foraging process, particul...
Studying the spatial-social interface requires tools that distinguish between social and spatial drivers of interactions. Testing hypotheses regarding the factors determining animal interactions often involves comparing observed interactions with reference or ’null’ models. One approach to accounting for spatial drivers of social interactions in re...
Urbanization imposes significant challenges upon wildlife worldwide, highlighting the need to understand how species and individuals respond to urban environments. Because animal behaviour is not fully plastic, these behavioural responses may also reflect consistent differences between individuals (behavioural types, BTs), or affect the covariation...
Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45...
Conservation translocations (reinforcements and reintroductions) are central for managing various endangered species, yet, their implementation is logistically and financially challenging. Because many translocations fail due to the mortality of released individuals, identifying and preventing these factors is crucial. Here we examine risk factors...
Uncovering the ways in which pathogens spread has important implications for population health and management. Pathogen transmission is influenced by various factors, including patterns of social interactions and shared use of space. We aim to understand how the social behavior of griffon vultures (Gyps fulvus), a species of conservation interest,...
Animal movement plays a key role in many ecological processes and has a direct influence on the individual's fitness. Movement tracks can be studied at various spatio-temporal scales, but the movement usually emerges from sequences of fundamental movement elements (FuMEs: e.g., a step or wing flap). The importance of movement in all aspects of the...
Time-of-arrival transmitter localization systems, which use measurements from an array of sensors to estimate the location of a radio or acoustic emitter, are now widely used for tracking wildlife. Outlier measurements can severely corrupt estimated locations. This article describes a new suite of location estimation algorithms for such systems. Th...
Host behavior and parasite infection reciprocally interact, but this dynamic is rarely studied experimentally in the field with multiple behaviors. We investigated the interplay between parasitism and host behavior via an in situ experimental tick infestation of a wild population of sleepy lizards, Tiliqua rugosa. Using Bayesian models, we assessed...
The feedback between host behavior and disease transmission is well acknowledged, but empirical studies demonstrating associations between individual’s pathogens or microbiota composition and their movement are rare. We investigated these associations in feral pigeons ( Columba livia domestica ), a synanthrope species known to host a plethora of zo...
Describing animal space use is essential for understanding their ecological needs and for planning effective conservation schemes. Notably, certain biomes and life histories are understudied due to methodological challenges in tracking animals in their natural habitats. Specifically, both arid environments and nocturnal species are not sufficiently...
Many environmental and ecological studies require line of sight (LOS) and/or viewshed analyses. While tools for performing these analyses from digital elevation models (DEMs) are widespread, they are either too restrictive, inaccessible or pricey and difficult to use. This methodological gap is potentially imperative for scholars using solutions li...
COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no c...
Social relationships among animals emerge from interactions in multiple ecological and social situations. However, we seldom ask how each situation contributes to the global structure of a population, and whether different situations contribute different information about social relationships and the position of individuals within the social fabric...
Background
Movement is central to understanding the ecology of animals. The most robustly definable segments of an individual’s lifetime track are its diel activity routines (DARs). This robustness is due to fixed start and end points set by a 24-h clock that depends on the individual’s quotidian schedule. An analysis of day-to-day variation in the...
Poisoning due to exposure to organophosphate and carbamate pesticides is a common threat for many wildlife species, especially for scavengers such as vultures. The Griffon vulture population (Gyps fulvus), for instance, is deteriorating in the Eastern Mediterranean, and is considered to be critically endangered in Israel, where 48 out of 107 (45 %)...
Background
There is growing attention to individuality in movement, its causes and consequences. Similarly to other well-established personality traits (e.g., boldness or sociability), conspecifics also differ repeatedly in their spatial behaviors, forming behavioral types (“spatial-BTs”). These spatial-BTs are typically described as the difference...
Spatial and social behaviour are fundamental aspects of an animal's biology, and their social and spatial environments are indelibly linked through mutual causes and shared consequences. We define the ‘spatial–social interface’ as intersection of social and spatial aspects of individuals' phenotypes and environments. Behavioural variation at the sp...
Habitat development may affect wildlife behaviour, favouring individuals or behaviours that cope better with perceived threats (predators). Bolder behaviours in human‐dominated habitats (HDH; e.g. urban and rural settlements) may represent habituation specifically to humans, or a general reduction in predator‐avoidance response. However, such carry...
Estimating key state variables such as abundance, survival, and recruitment of wild populations, and their interaction with local conditions such as precipitation, is essential for state‐dependent decision making and management. Estimation of state variables remains challenging, especially in species such as mountain ungulates inhabiting rugged and...
Quantifying animal movements is necessary for answering a wide array of research questions in ecology and conservation biology. Consequently, ecologists have made considerable efforts to identify the best way to estimate an animal’s home range, and many methods of estimating home ranges have arisen over the past half century. Most of these methods...
Fission–fusion (FF) societies are characterized by frequent changes in group cohesion, composition or size. While the ecological and social drivers of group size are well acknowledged, their effect on FF dynamics is largely unknown, partly due to lack of suitable data sets spanning multiple individuals and spatiotemporal scales. Theory predicts tha...
Parasites, ranging from microscopic viruses and bacteria to macroscopic worms and arthropods, are a fundamental part of life for all animals. Parasites affect almost all aspects of their host’s behavior, and conversely, host behavior affects parasites in countless ways. This book examines the many ways in which animal behavior and parasitism are in...
Background
There is growing attention to individuality in movement, its causes and consequences. Accumulating evidence demonstrates that conspecifics differ repeatably in their spatial behaviors, forming behavioral types (“spatial-BTs”), similarly to other well-established personality traits (e.g., boldness or sociability). Spatial-BTs are typicall...
Background. Movement is central to understanding the ecology of animals. The most easily definable segments of an individual’s lifetime track (i.e., movement path defined by a relocation data time series) are its diel activity routines (DARs). This definability is due to fixed start and end points set by a 24-hour clock that depends on the individu...
Home ranges (HRs), the regions within which animals interact with their environment, constitute a fundamental aspect of their ecology. HR sizes and locations commonly reflect costs and benefits associated with diverse social, biotic, and abiotic factors. Less is known, however, about how these factors affect intraspecific variation in HR size or fi...
Animal social relationships emerge from interactions in multiple ecological situations. However, we seldom ask how each situation contributes to the structure of a population or to the social position of individuals. Griffon vultures interact in multiple situations, including when roosting, flying, and feeding. These social interactions can influen...
Protected areas are intended as tools in reducing threats to wildlife and preserving habitat for their long-term population persistence. Studies on ranging behavior provide insight into the utility of protected areas. Vultures are one of the fastest declining groups of birds globally and are popular subjects for telemetry studies, but continent-wid...
Spatial and social behaviour are fundamental aspects of an animal’s biology, and the social and spatial environments are indelibly linked through mutual causes and shared consequences. Behavioural variation at the “spatial-social interface”, which we define as the intersection of social and spatial aspects of individuals’ phenotypes and environment...
Modern, high‐throughput animal tracking increasingly yields ‘big data’ at very fine temporal scales. At these scales, location error can exceed the animal's step size, leading to mis‐estimation of behaviours inferred from movement. ‘Cleaning’ the data to reduce location errors is one of the main ways to deal with position uncertainty. Although data...
Individual variation in movement is profoundly important for fitness and offers key insights into the spatial and temporal dynamics of populations and communities. Nonetheless, individual variation in fine‐scale movement behaviours is rarely examined even though animal tracking devices offer the long‐term, high‐resolution, repeatable data in natura...
Translocated animals typically find themselves in a novel environment in which they must establish a home range in a manner that will maximize their fitness. We hypothesized that the initial establishment of a home range is followed by adjustments expressed as home range shifting, and occurs as familiarity with the landscape increases, until the ho...
Vultures and condors are among the most threatened avian species in the world due to the impacts of human activities. Negative perceptions can contribute to these threats as some vulture species have been historically blamed for killing livestock. This perception of conflict has increased in recent years, associated with a viral spread of partial a...
Despite growing attention to the ecological and evolutionary importance of consistent individual differences in behaviour (animal personality), long-term field studies quantifying factors associated with behavioural repeatability remain rare. Here, we studied animal personalities over an 8-year period, representing 6 study years, in a wild populati...
Ecologists have long been interested in linking individual behaviour with higher level processes. For motile species, this ‘upscaling’ is governed by how well any given movement strategy maximizes encounters with positive factors and minimizes encounters with negative factors. Despite the importance of encounter events for a broad range of ecologic...
Several bird species have adapted to foraging in landfills, although these sites are known to represent significant sources of emissions of toxic semi-volatile chemicals including the halogenated flame retardants (HFRs) (e.g., polybrominated diphenyl ethers (PBDEs) and emerging compounds). The objective of this study was to investigate
the associat...
Modern, high-throughput animal tracking studies collect increasingly large volumes of data at very fine temporal scales. At these scales, location error can exceed the animal’s step size, leading to mis-estimation of key movement metrics such as speed. ‘Cleaning’ the data to reduce location errors prior to analyses is one of the main ways movement...
Timing of activity can reveal an organism's efforts to optimize foraging either by minimizing energy loss through passive movement or by maximizing energetic gain through foraging. Here, we assess whether signals of either of these strategies are detectable in the timing of activity of daily, local movements by birds. We compare the similarities of...
Timing of activity can reveal an organism's efforts to optimize foraging either by minimizing energy loss through passive movement or by maximizing energetic gain through foraging. Here, we assess whether signals of either of these strategies are detectable in the timing of activity of daily, local movements by birds. We compare the similarities of...
Significant portion of terrestrial landscape is shared with wildlife, inherently involving conflicts between animal conservation and agriculture (Lemly et al., 2000). Mammals and birds may damage crops directly by eating and trampling (e.g.,wild boars), or indirectly by damaging infrastructure, mainly irrigation systems. We used motion sensitive ca...
1. Ecologists have long been interested in linking individual behavior with higher-level processes. For motile species, this 'upscaling' is governed by how well any given movement strategy maximizes encounters with positive factors, and minimizes encounters with negative factors. Despite the importance of encounter events for a broad range of ecolo...
Individual hosts vary substantially in their parasite loads. However, whether individual hosts have consistently different loads remains uncertain. If so, hosts that have consistently high parasite loads may serve as key reservoirs or super‐spreaders. Thus, identifying whether individuals persistently differ in their parasitism and the factors that...
Understanding the drivers promoting sociality over solitariness in animal species is imperative for predicting future population trends and informing conservation and management. In this study we investigate the social structure of a desert dwelling population of striped hyena Hyaena hyaena. This species is historically regarded as strictly solitar...
Adriana A. Maldonado-Chaparro and Damien R. Farine, Demographic processes in animal networks are a question of time Amiyaal Ilany, Complex societies, simple processes Orr Spiegel and Noa Pinter-Wollman, Placing the effects of demography on networks in ecological context Ipek G. Kulahci, Individual differences can affect how networks respond to demo...
Decision-making agents face a fundamental trade-off between exploring new opportunities with risky outcomes versus exploiting familiar options with more certain but potentially suboptimal outcomes. Although mediation of this trade-off is essential to adaptive behavior and has for decades been assumed to modulate performance, the empirical consequen...