Mother Goose…Queen of Fertility

Everybody loves Canada geese (Branta canadensis). They are the role models of the bird world, beautiful, intelligent, smart, mate for life, excellent parents, survive harsh environmental conditions, battle Mother Nature, migrate and navigate thousands of miles in all kinds of weather.

But geese are similar to fertilizer, as in the old farm saying: “A little fertilizer is good but more is not better”.

As urban sprawl invaded the country, conversion of farm land into suburban areas included many ponds. Combining practices ofmowing grass for greenbelts around ponds andthe decline in natural predators led to a significantincrease in resident geese populations. Over the last 30 years in the northern and mid-Atlantic states east of the Mississippi, Canada geese have become a pond meister’s worst nightmare. It usually starts out as people enjoying watching, feeding and caring for them and in a couple of years the pond experiences excessive algal and aquatic plant growth from geese feces nutrient-loading. Unlike most birds, Canada geese eat grass, up to four pounds a day per goose. They like to feed where grass is low and visibility long-ranging, for a good view of any approaching predators…which describes ponds, lakes, golf courses, parks, playgrounds, schools, soccer fields, and airports. The overall impact of geese waste in ponds depends on several factors including size, depth, turbidity, fetch, natural chemistry (oligotrophicversus eutrophic), the abundance of geese and the rate at which other nutrient sources (fertilizer runoff, manure from livestock, sewage, etc.) including organic matter (leaf and grass cuttings) enter the pond. I have found if there is an excessive growth of algae and aquatic plants in a pond, that it is usually associated with increased nutrients (nitrogen and phosphorus) from some source. Several peer-reviewed papers have studied the effect of goose feces on water chemistry. Manny et al. (1975, 1994) was the first to assess nutrient contributions to lakes by geese. They estimated the total contribution to nutrient-loading in a lake from geese was as high as 40% of the nitrogen and 85% of the phosphorous. Other researchers supported these findings. Unckless and Makarewicz (2007) published studies suggesting these claims were not correct from conducting a series of mesocosm (mid-sized environment) experiments. They found goose feces simply sank to the sediment whereat eventually became part of the benthic detritusfood web. This led them to suggest that goosefeces were unlikely to have immediate impacts,but that over time the buildup of nutrients in thesediment may have significant effects on thewater body. They did suggest these nutrientscould be cycled back into the water columnduring a mixing event and stated that greaterresearch was needed to determine the fate ofgoose feces in the sediment.Their research was not representative oflimnology in small shallow ponds, where windplays a greater role in mixing water masses tha