On a mild summer morning, a wildlife photographer paddles into the headwaters of a New Jersey lake hopeful for a chance at some memorable shots. As she rounds a bend in the creek, a Canada goose brood resting on a mossy hummock provides for an exceptional photo that she will use to adorn her den. Meanwhile, across town, a zealous linebacker tackles a high school football fullback during a grueling practice session. The fullback stands and looks with disgust at his now green-stained, white jersey and uses his fingers to flick away the goose feces that are wedged in his helmet’s facemask. Love them or hate them, resident Canada geese have expanded their population in recent decades resulting in mixed impacts on humans who share the land with these stately birds.
The opportunity to observe, study and hunt resident Canada geese has been a positive aspect of their increase; however, nuisance and damage problems have developed. Understanding the population dynamics of resident Canada geese is critical to properly manage this species. To accomplish this, New Jersey Division of Fish and Wildlife researchers and other collaborators are designing a comprehensive population model that will incorporate information on productivity, annual survival, movement, harvest, population control and other demographic factors. The ultimate use of such a population model is to understand how the various factors affect the resident Canada goose population, especially which factors are most important in limiting population growth. A comprehensive resident Canada goose population model will allow waterfowl managers to select actions most likely to meet management objectives and also predict both the outcome and the timeframe needed for any proposed action.
A key component in the development of this model is the annual production of young birds into the population, generally termed “recruitment” by biologists. Arctic-breeding, migrant Canada geese are subjected to harsh and unforgiving spring breeding season conditions. In contrast, resident geese experience relatively tranquil spring breeding conditions, allowing them ample time to produce and rear their young. Human development of urban and suburban areas throughout the state has provided both an increase in the quality and quantity of breeding habitat for resident geese, and a refuge from hunting pressures and predators. The expansion of corporate parks and recreational areas with manicured open lawns and artificial water sources has created an ideal habitat for the nesting and brood rearing of resident geese. This development has also decreased the amount of land suitable for hunter harvest, limiting the major mortality factor of these birds. Consequently, resident geese, on average, are more productive, recruit more birds into the population each year, and survive at a higher rate than their migratory counterparts.
The recruitment portion of the comprehensive population model under development will incorporate historic data collected in New Jersey during the 1980s and 1990s as well as data collected during the 2009 and 2010 breeding seasons. New Jersey Division of Fish and Wildlife has collaborated with the University of Delaware to conduct the most recent years study on productivity and recruitment of resident Canada geese. Researchers locate and monitor nests throughout the state to determine how many offspring are produced, and how variables such as predators and weather conditions affect nesting success. In addition, researchers perform a mark-recapture study of goslings from hatch until fledge to determine the survival of these birds during their most vulnerable life stage. Recruitment data from these studies will play a major role in completion of the resident Canada goose population model.