Laura Erickson's For the Birds

Conserve water.

One of the most important ways we can help birds is to conserve water. How critical is that for birds? Let’s just consider one situation: that of the Aransas National Wildlife Refuge, along the Gulf of Mexico on the Texas coast. People have known for a long time that the fresh water flowing into the refuge is critical for Whooping Cranes and other species that live in the estuary. On November 16, 1992, there was a report in the San Antonio Light newspaper about the water needs of Whooping Cranes. The article stated that whoopers, just like humans living in San Antonio and other Texas cities, depend on water from the Edwards Aquifer, a source of spring water that feeds the Guadalupe and San Antonio Rivers. Of course, rainwater and runoff also provide fresh water for the rivers, but during dry spells, aquifer springs may contribute more than 80 percent of the fresh water entering the bay. When people remove this aquifer water for drinking, bathing, irrigation, feeding livestock, manufacturing, etc., the fresh water entering the estuary from the rivers declines, salinity goes up, and the ecosystem changes.

During years when not enough fresh water flows from the rivers into the estuary, marsh salinities go up and blue crab populations decline. Since blue crabs are the primary food source for wintering Whooping Cranes, a scarcity of crabs in the marshes hurts the cranes. In years when salinities are high and blue crabs are few in number, Whooping Crane winter deaths increase. “We found when salinity in the marshes reach 23 parts per 1,000 (and sea water is 35 parts per 1,000), the whooping cranes have to fly to fresh water to drink at least twice a day. This forces the cranes to use up more energy reserves, and increases the risk of predation whenever the birds leave the marsh,” Tom Stehn, Whooping Crane coordinator at the Aransas National Wildlife Refuge, reports. The cranes that survive have less to eat and are forced to use up fat reserves rather than putting on fat. Fat reserves are important for the cranes to make their 2,400 mile migration in the spring and also make it through the nesting season. There is a direct correlation between Whooping Crane breeding success in summer and the population level of blue crabs they fed on the previous winter.

It’s not only Whooping Cranes that depend on fresh water inflows to the estuary. Other endangered or threatened species that live in the bay include Brown Pelicans, Reddish Egrets, and Piping Plovers. The human population of Texas is expected to double in the next 50 years. Is it possible for humans to meet our own needs and those of Whooping Cranes and other birds?

The heavy needs of water for irrigation and supplying the needs of the burgeoning development of central Florida has put Everglades National Park in jeopardy; the flow of the Platte River through Nebraska, where Sandhill Cranes stage every spring, is a fraction of its historical level; and much of the arid West is becoming more arid. Even in areas of the country that have a lot of fresh water, such as the Great Lakes region, ground water and drinking water supplies are becoming more and more contaminated due to intensive agriculture practices and use by individuals. When sewage plants carry too heavy a burden, managers sometimes hasten the treatment process by releasing blended contaminated and cleaned water together, which increases the dangers of disease for both humans and birds. For example, one dangerous organism, Cryptosporidia, got into Milwaukee’s drinking water in 1993, causing illness in about 400,000 people. More than 100 people, mostly those with impaired immune systems, died.

In Duluth, where I live, a series of storms in September, 1990, caused storm sewers to overflow, washing raw sewage and even some medical wastes into Lake Superior. And suddenly birders and Duluthians were discovering sick and dead birds all over along the shore. One birder brought me three sick Sanderlings that she found, weak and emaciated, along a popular beach. Parasites multiply rapidly on birds too sick to preen, and these birds were covered with lice and mites. I dusted them with a mild insecticide, but meanwhile, when I first examined the birds, a louse on the sickest bird bit me. A couple of days later I became seriously ill, with a high fever, hallucinations, and difficulty breathing. My symptoms were similar to psittacosis (parrot fever), but blood titers proved negative for that and every other disease the blood samples were tested for. Meanwhile, my doctor laced me with a broad-spectrum antibiotic and I recovered. But the sanderling died, and a nighthawk I was caring for at the same time also succumbed. We Duluthians swim and boat in Lake Superior, and draw our drinking water from it, all the while leaking our wastes into the water and trusting that human beings will prove a bit sturdier than three-ounce Sanderlings.

As our public utilities become more and more burdened with our growing population, and the anti-tax movement makes it harder and harder to maintain these public utilities, we can expect this kind of dangerous situation to happen more and more, hurting all of us. Conserving and using our precious water resources responsibly helps birds and humans both.