Human Disturbance

Quarterly Journal of PRBO Conservation Science. Number 131, Winter 2003. $3.50 131 ObserverMinimizing impacts on wildlife Human Disturbance Melissa Pitkin Contents When you go out for a day at the beach non-native shrub in a yard results in or a hike in the woods, what do you take broader consequences on a large scale. with you? Probably a daypack, water bot- Whether direct or indirect, disturbance Human Disturbance . 1 tle, perhaps binoculars and a camera, often results from situations where indi- Executive Director’s Column . 2 some food, and a few other essentials, viduals are unaware of the impact of their right? I would like to add to your list of actions. With awareness, beachgoers may Vulnerable Coastal Habitats . 3 essentials one more item, a big one, per- decide to walk on the wet sand away from Invasive Plants . 5 haps the most important: awareness. By nesting habitat, and a backyard land- Responsible Science . 6 this I mean awareness of the surrounding scaper may choose to plant a native shrub ecosystem and the effects your actions that will provide bird habitat while help- Birding Ethics . 9 may be having on it. ing to keep neighboring parks and open Focus on Feeders . 10 This Observer is devoted to the topic spaces as functioning wildlife habitat. of human-caused disturbance in ecosys- At PRBO, we develop recommenda- Planned Gifts to PRBO: IRAs . 12 tems. Through our daily routines, recre- tions to minimize the negative effects of Spain Oil Spill . 13 ational and occupational activities we human-caused disturbance on birds and Calendar . 16 humans impact wildlife and their habitats other wildlife populations. And our in a variety of ways. Let’s face it, we are research protocols are designed to limit part of the ecosystem: our actions result our effects on the wildlife we are attempt- in reactions, from negligible to severe. So ing to protect. For our land management what defines human-caused disturbance? partners we provide recommendations on Human-caused disturbance occurs when how they can alter their operational activ- our actions result in behavioral or physi- ities to avoid disturbance to birds. For cal changes to wildlife or their habitats. homeowners we develop recommenda- Human-caused disturbance can be tions on appropriate landscaping prac- direct or indirect. Imagine two people tices. For scientists we develop protocols walking on the beach in mid-June, for emphasizing nonintrusive study methods. example, enjoying the waves, the sand, For wildlife and outdoor enthusiasts we and the fresh air. They’re talking and produce informational handouts with tips don’t notice a small, sand-colored shore- on limiting recreational disturbance. bird flush from its hidden nest, or the soft There are simple things we all can do to sound of its three tiny Snowy Plover eggs minimize our negative impacts on wild- crushed underneath a shoe. Their actions life—and awareness is the first step. directly caused the nest to fail. Or, imag- In this Observer, the stories you will ine that your neighbor plants Scotch read demonstrate both that humans are Broom (Cytisus scoparius) in her back- part of the ecosystem and that greater yard. The next spring its seeds are spread human awareness can help us be respon- to nearby parks and open spaces. When sible members of healthy ecosystems. these invasive plants grow, they displace native plants, reducing available native Melissa Pitkin is PRBO’s Education habitat for many songbird species. In this Director. case, disturbance is indirect: planting the 2 PRBO Conservation Science. Winter 2003. Number 131. Ellie M. Cohen PRBO Some forms of human-caused disturbance can be balanced with thoughtful alternatives. To conserve biodiversity Applying PRBO’s Bird Studies Ellie M. Cohen The word is out—birds are excellent (Mono Basin, eastern Sierra) are using PRBO’s New Look indicators of ecosystem health. our recommendations to plan their As threats to our environment con- designs, e.g., choosing tree and shrub I am proud to formally introduce tinue almost unabated, interest in species that support nesting songbirds. applied bird conservation science is soar- ♦ our new Observer, another step in The Nature Conservancy and U.S. Fish ing. From the National Park Service to and Wildlife Service (Cosumnes River, PRBO’s transition to an updated The Nature Conservancy, more and Central Valley, California) removed and consistent communications more public and private interests are levees, allowing for regular flooding of asking PRBO for help. riparian habitat. The resulting diverse package. PRBO’s new “signature” By studying bird populations, PRBO is plant growth is contributing to is vibrant and vivid, conveying our able to evaluate and even predict effects increased bird diversity and abundance. on wildlife of changes ranging from West ♦ The National Park Service (Point role as catalysts for effective Nile virus and global warming to planned Reyes) and California Department of conservation science! habitat restoration. This enables us to begin to answer a fundamental question: Parks and Recreation (Monterey Bay) protect Snowy Plovers’ beach nesting We are most grateful to the San how do we balance human actions with the urgent need to conserve biodiversity? sites each summer (see next page). Francisco Foundation for a Based on our long-term studies, PRBO ♦ The California Department of Fish and generous grant and to the is providing recommendations that are Game (Marine Region) has listed the now in use by every major habitat and declining Xantus’ Murrelet as a candi- wonderful people at Interbrand for wildlife management agency in the West! date for “threatened species” status. To their essentially pro-bono effort that Following is a sampling of recent PRBO- protect nesting birds from nocturnal made this project a reality. recommended changes to wildlife and predators, the agency also seasonally habitat management protocols. bans nighttime use of lights by Califor- ♦ nia’s squid fishery within one mile of the – Ellie M. Cohen Golden Gate National Recreation Area now avoids disturbance of song- Channel Islands (off Santa Barbara). birds during the breeding season when Some forms of human-caused distur- conducting habitat restoration and bance can be balanced with thoughtful general maintenance, and has changed alternatives such as those outlined restoration planting to enhance bird above. With human activities continuing breeding habitat (see page 5). to threaten bird populations and other ♦ The National Park Service prohibits wildlife—with likely impacts, ultimately, construction and has closed certain on each of us—PRBO’s research is pro- areas to public access on the highly viding the sound scientific foundation popular Alcatraz Island (in San needed to guide successful, win-win con- Francisco Bay) during the seabird servation solutions. breeding season. Ellie M. Cohen is PRBO’s Executive ♦ Plant ecologists conducting restoration Director. on Rush and Lee Vining Creeks PRBO Conservation Science. Winter 2003. Number 131. 3 Beach-nesting Snowy Plovers are vulnerable to disturbance. DAVE DIXON DAVE Today, birds of rocky shores and sandy beaches must cope with human-induced pressures. Where land and sea meet Finding a Balance Sue Abbott Seabirds, shorebirds, and waterfowl— road vehicles is a challenge for which outreach and increased PRNS ranger the waterbirds—possess amazing adapta- they are not well equipped. presence on beaches, particularly during tions, enabling them to survive in rugged In 1999 and 2000, PRBO studied weekends and holidays. PRNS has and exposed coastal and marine environ- Western Snowy Plover chick survival on implemented a unique outreach program ments. The Common Murre, for example, beaches in Point Reyes National in which rangers work closely with lays an oblong egg designed to stay put Seashore (PRNS), California. We com- PRBO biologists. Using up-to-date infor- on the narrowest rock ledge. The Black pared chick survival on weekends and mation from biologists about sensitive Oystercatcher, employing keen aware- holidays, when human recreation is high- chick-rearing areas, PRNS can focus out- ness of tidal cycles, nests within feet of est, to that on weekdays. Significantly reach efforts to minimize disturbance on the pounding Pacific—prime intertidal more chicks were lost on weekends and those high priority sites. real estate for this mollusc lover. Water- holidays in both years, suggesting that On the infamous rocky shores of birds can survive and even thrive in human recreation reduces Snowy Plover Alcatraz Island, California, PRBO biolo- harsh natural conditions. chick survival. Based on these findings, gists have a unique challenge: to observe Today, though, birds of rocky shores PRBO recommended using educational an assemblage of breeding waterbirds and sandy beaches must also cope with and the many humans that recreate and human-induced pressures, such as lim- work on and around the island. The ited habitat availability, human popula- Brandt’s Cormorant is the most numer- tion growth, and our increasing desire ous breeder on Alcatraz; in fact, the num- for recreation in formerly remote places. ber of nesting pairs increased by 19% We now are learning how our actions between 2001 and 2002, reaching the can upset delicate balances in the life highest numbers ever recorded. During cycles of birds, particularly during the May 2002, while these sleek, iridescent, short window of time when birds must black seabirds were at their busiest incu- find a mate, build a nest, incubate eggs, bating eggs and rearing chicks, 116,000 and raise young. On the West Coast, this people toured Alcatraz! It’s not surpris- time window, March through September, ing that humans and birds sometimes coincides with our spring and summer interact in such close quarters. recreation booms. In the past three years, we docu- It is no coincidence that two birds mented disturbance to birds on and dependent on West Coast beaches for around Alcatraz at some of the highest nesting habitat are either federally levels on record.

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