A critical part of wildlife management is understanding how wildlife moves within its habitat. We will break down the first of the two types of movement: Local Movement.
There are four main types of Local Movement:
- Home Range: a home range is the area traveled by an animal in its normal daily activities. An animal must find the all its habitat requirements within its home range; otherwise it will extend its movements. Sedentary animals may have only one home range (ex. black tailed deer)
- Seasonal Home Range: some species normally have several home ranges that are used seasonally (e.g., summer range, winter range), sometimes in conjunction with annual migration. Seasonally used home ranges do not fulfill year-round habitat requirements, only seasonal habitat requirements.
Sizes of home ranges vary among animals. Home ranges are often larger for males than for females of the same species. Home ranges in good habitat are typically smaller than in poorer habitat because animals do not have to travel as far to fulfill their needs!
- Critical Habitat: critical areas are parts of home ranges where limiting habitat resources are located – they have also been termed “Key Areas”
- e.g., watering areas for Desert Bighorn Sheep
- river floodplain as critical moose winter range
- nesting sites for raptors
- south-facing slopes for big game
Maintaining a productive wildlife population depends on protecting critical areas from degradation or destruction.
Most species of birds and mammals defend an area against other members of their species, and this defended portion of the home range is called their Territory. Territorialism may be seasonal and is often associated with periods of reproduction. They are often maintained by intensive marking of the area with visible signs and/or with scents (ex: wolves=scent posts; bobcats=scat piles)
- Provide for uninterrupted breeding and care of young
- Provide an adequate food supply for critical seasons
- Serve as a mechanism to prevent over-crowding
Animals holding territories assure themselves of habitat resources and mates. They tend to be successful in survival and reproduction.
In many territorial species, there are excess, nonterritorial animals existing in substandard habitats or constantly moving among occupied territories, so called “floaters” (e.g., “satellite bucks”)
Dispersal: dispersal movements fall into two categories:
- Emigration is movement OUT of a previously occupied area; it is the permanent abandonment of an area
- Immigration is movement INTO a new area; movement into a previously unused area
With some species, dispersal substitutes for mortality as a mechanism that relieves overcrowding, (e.g., marmots, beavers, foxes). Dispersal permits a species to spread to new areas. Some animals are good dispersers (very adaptable, with wide range of habitat tolerances, pioneering species – e.g., coyote, opossum, armadillos). Other species are very poor dispersers, (e.g., bighorn sheep).
Understanding the local movements of your wildlife is extremely important to managing their needs! Remember – a good home range can benefit the animals you already have plus their future generations! Next post we’ll discuss Migration – the second type of movement!