Gathering information by observing individuals in their natural setting.
Field research (“fieldwork”) refers to information gathered by observing individuals in their natural setting. Field research can be both qualitative and quantitative in nature. Qualitative research emphasizes the importance of observing variables and their interactions. Quantitative research attempts to objectively gather data to make associations, comparisons, and predictions among variables. Field studies that sought to associate behavior with inter-individual interactions and/or the environment formed the foundation for the field of behavioral ecology (Martin and Bateson 2007).
Field research involves observations of free-living wild animals in their natural habitats while minimizing perturbations or disturbances to their environment or behavior. Field excursions may require some or all of the following (Lagler 1956): funding for travel, salary, supplies, and lodging; field assistants to help with data collection; information about the area; planning and coordination; and a schedule of tasks to be completed. Fieldwork may involve the observation, capture, and measurement of animals and collection of environmental data. Documenting the environment of the population under study is an interdisciplinary effort that may require knowledge of surveying, geology, chemistry, and botany.
Field studies can provide insight into the causes and complexities of animal behavior. Animals regularly interact with their environment through activities associated with breeding, eating, and movement. More accurate information may be obtained about these behaviors if they are studied in wild versus captive animals because captive individuals are often too constrained by artificial environments to behave naturally. Furthermore, evidence that a variable can influence behavior under laboratory conditions does not mean that it influences behavior of wild animals. Field studies, therefore, are invaluable for observing the full range of an animal’s behavior and understanding its ecological context. Observers are able to note the circumstances in which behaviors do and do not occur, which allow them to infer their function and proximate causes (Martin and Bateson 2007).
Exploratory data obtained from field observations can form the basis for follow-up experimental studies in artificial settings that can experimentally test for causality. Field studies aid understanding of how a behavior is adapted to a particular environment. Habitat can influence behavior, so it may be important to choose study sites that are in different environments to be able to generalize a species’ typical behavior (Martin and Bateson 2007). Scientists can conduct controlled field experiments, in which certain aspects of the environment are manipulated to test a hypothesis. For example, to test weaverbirds’ abilities to differentiate between their own eggs and those of other parents, researchers planted nests with the eggs of other parents (Lahti and Lahti 2002). By experimentally manipulating gull eggshells, Tinbergen (1962) learned that parents remove broken eggshells to reduce predation by crows.
Goals of Field Sampling
Field studies can help scientists understand how individuals or species interact within populations or ecosystems, anthropogenic effects on individuals or populations, and a population’s life history characteristics. Knowing the natural history and ecological context of organisms is also helpful in conservation efforts. Studies can focus on the distributions of populations/species, the presence/absence of a species in a given area (particularly a species that is threatened or invasive), determination of environmental limitations or advantages for a population, or obtaining specimens for further study in the lab.
Types of field observations, goals, sampling methods, and potential difficulties (Bart et al. 1998)
Type of observation
Estimate time spent engaged in different behaviors
1. Scan sampling
2. Focal sampling
1. Observer influences behavior
2. Animals disappear out of sight
Estimate trends in population size in time or space
1. Changes in survey efficiency can influence estimates
2. Defining the trend in population size
3. Missing data
4. Variation in observer skill
Estimate the number of individuals that survive in a given time period
2. Nesting success
1. Finding and following all nesting attempts
2. Monitoring efforts unevenly distributed over time
Determine why animals use some areas or consume some food items while not using or consuming others
1. Surveys of habitat use
2. Behavior sampling
A description of an individual in the wild may include any or all of the following characteristics (Lagler 1956)
Genus and species
Where is the organism found?
How do the current and original ranges vary?
What ecological factors influence the size of the range?
What ecological factors influence distribution?
How do they change throughout development?
How selective is the individual in choosing food?
Does diet vary seasonally?
What are the daily food requirements?
How often does the organism eat?
How do they eat?
What factors influence what food is eaten and when?
What is the organism’s age, length, and weight?
Does the organism exhibit allometric growth?
What factors influence growth?
When is sexual maturity?
What is the sex ratio?
Are there courtship rituals?
When and how do individuals breed?
How fertile are individuals?
Do they exhibit parental care?
What is the offspring’s survival rate?
Are the breeders oviparous or semelparous?
What factors influence reproductive success?
What are critical environmental windows?
When does hatching occur?
How long is larval development?
What factors influence development?
What movements are observed?
Does the species migrate?
Do individuals school?
Are they territorial?
Do you observe individuals learning?
Are individuals engaging in social behaviors?
What factors influence behavior?
Field notes typically contain detailed descriptions of the physical environment and individuals under study, including their behavior and communication with others. Methodological notes describe how data are acquired as well as justification of techniques used and may incorporate ideas for future studies.
When reporting the results of field studies, the following characteristics should be included as appropriate (Lagler 1956)
Nearby geographical features
Map, including source and cardinal directions
Extent of development
Size of field site
Presence of dispersal corridors
Extent of pollution
One or a combination of sampling techniques may be employed (Bart et al. 1998). Simple random sampling refers to a situation in which all possible samples from the population are equally likely to be selected. Random sampling is not always feasible in natural settings, so nonrandom sampling may instead be used, particularly with regard to selection of focal animals. Researchers may choose to focus on individuals at a particular developmental stage or focal individuals distributed evenly across a population.
Sources of Error
Both observer influences on behavior and measurement bias are potential sources of error in field studies (Bart et al. 1998). It is not uncommon for animals to change their behavior in the presence of an observer, and the extent to which animals are affected may depend on species and/or life stage (Martin and Bateson 2007). Therefore, an acclimation or acceptance period may be required if the animal appears to react to the researcher. Acclimation periods are typically short but vary depending upon the species being studied. The presence of an observer can also influence the behavior of the focal species’ predators or prey. As a result, it is important for the observer to minimize disturbances and wait until after the acclimation period to collect data.
Hides or blinds may reduce disruption, but can restrict the observer’s ability to monitor individuals. An animal moving out of sight can result in selection bias, when data are not recorded at the scheduled time, or measurement bias, if the individual is hidden for only part of the scheduled observation time. While the use of a hide or blind reduces the ability of animals to see the observer, it does not prevent the animals from detecting the observer’s sounds or smells. To further minimize the likelihood of disrupting normal behavior, remote video cameras may be used. While they may not be able to observe all of the behaviors of the individuals under study, resulting in selection and/or measurement bias, they create a permanent record of the behavior that can be replayed and may also help detect behaviors that occur so rapidly that they are difficult to record accurately in real time (Martin and Bateson 2007). An additional benefit of having a permanent record of behavior is that follow-up studies may be conducted without having to return to the field site. Recorded behaviors may also be used as educational tools or deposited into open-access databases that are used by the research community.
Prominent Field Researchers
In the mid-1800s, Charles Darwin developed his theory of evolution by natural selection after conducting field observations of a variety of species while voyaging on his ship, the Beagle, and studying the plants and animals that were local to his home in England (Darwin 1859). In the 1920s–1930s, Margaret Morse Nice captured and marked sparrows in her yard and studied them throughout their development (Nice 1937). In the 1930s–1950s, Konrad Lorenz, Karl Frisch, and Nikolas Tinbergen developed the field of ethology, or the science of animal behavior. Their studies of numerous animal taxa, including birds, fish, and insects, helped researchers to better understand the causes of behavior, its evolution, and how it relates to fitness (Dewsbury 2003). At about this same time, J.H. Crook and David Lack used their studies of birds to develop a comparative approach to behavioral ecology in which they associated behaviors with the birds’ environments (Lack 1947; Crook 1964). Jane Goodall began working with chimpanzees in Tanzania in the 1960s (Goodall 1990). Through her decades of field observations, she greatly increased our understanding of primate behavior and documented behaviors that were previously thought to be unique to humans, including tool use and warfare. Her work has helped protect wild primates and has publicized issues of animal conservation.
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