Birds after Hurricane Sandy
by Mary Jasch
There are two ways Hurricane Sandy affected birds on our East Coast shores. One is the direct effect on birds during the storm and the other, larger effects, are the changes in habitat, says Marshall Illif, Cornell Lab of Ornithology Project Leader, Avian Knowledge Network and eBird.
Direct Effects on Seabirds
Unless you are a birder, the realization that seabirds truly eat, live and sleep on the ocean, coming to land only to nest is astonishing. These seafarers are affected by hurricanes, especially large birds such as shearwaters, storm petrels, terns and jaegers. “They seem to move out of the way as best they can and fight the winds,” says Iliif.
Most birds cannot fight 100 mile per hour winds so they are swept up in the hurricane, especially tropical ocean birds, blown to land and dropped as the hurricane weakens. Weakened birds usually fall into woodland and are eaten. Stronger birds usually find habitat on a lake or river where they stay until they’re able to return home to the ocean.
Storm Petrels never occur inland but have been seen, since Sandy, inland on lakes and rivers in New York, New Jersey and Pennsylvania, and birders have observed Peregrine Falcons killing them, which is not normal since their habitats are entirely different.
“Storm Petrels end up far from home, the majority are seen by birders flying back to the sea, so maybe there’s a 50-5- chance for their survival,” Iliff says.
Historically, the northernmost appearance of the tropical Sooty Tern is just off the coast of southern Florida where it breeds. This bird spends its time flying the Caribbean where large numbers get caught up storms. Over the past few decades, they’ve been sighted inland and now in Yonkers, Philadelphia and Waterbury, Connecticut.
“All birds will try to get back to the ocean as quickly as they can and maybe able to fly back south,” Iliff says. “There is some avian mortality as a result of Sandy. Unless it’s a very rare seabird, most species do ok with hurricanes because they deal with hurricanes all the time.”
Larger Effects: Changes in Habitat
Wind blows down trees in woodland and creates gaps. Birds that use closed canopy forests are then out of a home. The new, sunny forest gaps become “edge” habitat (open areas with adjacent woodland) and home to different bird species. Birds such as the Wood Thrush lose habitat; others, such as Indigo Bunting, gain. So does the American Woodcock, the only shorebird that breeds in the forest edge.
Winds and tides cause changes to beaches and barrier islands – erosion, dumping of sand, drowning and removal of vegetation. As with the forest gap, a wiped clean beach results in lost nesting area for some birds, but opens up breeding sites for others such as the Piping Plover, Least Tern and American Oyster Catcher.
Long Beach Island used to be a vacation spot for the human population. Where once there where house, now there is sand, says Iliff, and an argument can be made it’s not a safe place for people to live. Now there are questions about what will happen with the land. If left in a natural state, it will be habitat for native birds.
“The most prominent effects are the changes in beaches, which is a natural occurrence due to winter storms and hurricanes. Beaches constantly change – it’s a dynamic thing. Piping Plovers are a concern. When wide open beaches are built up, they lose breeding ground. There is a lot of competition with people for sandy beaches.”
Barrier islands like Long Beach Island are dynamic, constantly changing. Their natural pattern consists of being sometimes underwater, sand shifting, brush areas grow and are washed away, and natural cuts form from storms and create bays or inlets. Storms wash away habitat for one species, but favor others like the Piping Plover, threatened Federally and in NJ, MA and CT and endangered in NY and PA.
“Sand moves in and out of inlets, resulting in the creation and loss of islands. And sandy islands are where these birds like to nest,” Iliff says.
Sandy Hook and Breezy Point in Gateway National Park have changed significantly since the hurricane. “Whatever birds that bred in that holly forest, like the Black-capped Chickadee, whose southernmost limit is the New York/New Jersey coastline….”
American Holly Forest Devastation
In Gateway National Recreation Area, the American Holly forest on Sandy Hook where the Black-capped Chickadee lives, was flooded for a while from over-wash.
“It’s difficult to know if the plants have died. Over the next growing season we’ll be assessing that,” says Dave Avrin, GNRA Chief of Natural Resources Management. “Salt spray and over-wash affected some pines, particularly white, but whether they’ll die or leaf out, we won’t know until spring. They’re all brown.”
Avrin is optimistic because wildlife that using these areas are adapted to it, storms and all. “It doesn’t look like a total loss. My expectation is that it will be ok providing needs to wildlife are met. Until we go through a growing season, it’s too early to tell. It wasn’t so much a wind issue; it was a tidal issue.”
The biggest physical impact in the natural area is from over-wash, he says. The dunes in the Rockaways (NY) are pretty much flattened for many yards going inland, which is not unusual from a storm. Avrin believes that over time they’ll reform themselves. Although birds don’t nest in the dunes themselves, the dunes protect plants on the landward side from salt spray and salt carried by wind.
Coastal Winter Raptors
It’s too early to tell if there will be any effect on migratory birds. The most dramatic effects have been on coastal winter raptors, says Pete Dunne, Chief Communications Officer for New Jersey Audubon and Director of Cape May Bird Observatory, Cape May, NJ.
“The numbers are down for Red-tailed Hawks and Northern Harriers. An estimate is 75 percent because their prey base has been diminished by tidal flooding. Rodents that live in the marsh were killed and not enough time elapsed to restore their populations before migrant raptors arrived. Most raptors flew on and those that remained have a hard time finding prey.”
This was the most dramatic observation. “It didn’t take them long to leave. They’re professional birds; they know what they’re doing.”
In August of 2012, Hurricane Irene devastated the rodent population too, but they had several months to restore themselves before wintering raptors arrived.
“In a normal winter I see 40 to 50 Northern Harriers in a 360 degree scan. This year I saw 14. That’s more than I anticipated,” says Dunne. “Dramatic changes like this are built into the system Predators and prey and the environments that sustain them both have been working this out for thousands of years. There are other, more long-term impacts on sandy beaches. There is a good deal of floating vegetation pushed into upland areas that will have secondary impacts on birds that return in the spring and also resident species. Storms are periodic and Nature deals with periodic catastrophes.”
The greater question, Dunne says of the 1,000 pound gorilla in the room, is rising sea levels. That impact on coastal breeding birds is going to be more perilous. “Coastal breeding birds in coastal marshes are undergoing a 30-year decline in population due to more routine flooding in breeding seasons. Northern Harriers have gone from 50 breeding pairs in New Jersey down to 10.”
Salt marsh sparrows are specialized to be in the high marsh near the ecotone (where the marsh meets the forest). Their numbers are declining because the hydrology of salt marshes is changing. The more wet-site tolerant Spartina alterniflora (saltmarsh cordgrass) is taking over and diminishing the habitat of the drier, Spartina patens-dominated high salt marsh. (S. patens is salt hay, garden mulch.)
Says Marshall: “There are much greater risks in the world than hurricanes. Rain forest decline and sea level rise due to climatic change are much greater perils for birds than one storm that’s a natural occurrence. As sea level rises there are going to be more serious impacts from these storms.
“When salt marsh is lost by the tides, it takes a long time to rebuild. It washes away and goes underwater. Salt marshes get ditched and drained and that affects salt marsh birds. Salt marshes can’t renew fast enough. They could never recover by moving inland where there are bulkheads and rip-rap. This is one of the most pressing issues.”
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published February 01, 2013