Tuesday, August 2, 2011

A Place for Wildlife

A walk on Willard Beach with Laura Zitske of Maine Audubon

Chris Hoffman from SMCC introduced Laura Zitske of Maine Audubon, a wildlife ecologist and director of the piping plover and least tern recovery program. She passed around a baby and adult piping plover in shadow boxes (the birds died of natural causes). Everyone introduced themselves to establish what people would like to learn from this field trip; most participants wanted to learn beach wildlife with an emphasis on piping plovers. Because of high tide, Zitske focused on the beach and above. Piping plovers do not nest on Willard Beach but are found nesting on Maine’s sandy southern beaches.

Humans love the beach; however, it is a very stressful place for wildlife. It ranges from cold, windy, and rainy to scorching hot; these are extreme dynamic temperatures. There is no shelter like a forest canopy; being able to burrow into moving substrate is one coping mechanism. Other wildlife use the beach as a place to pass through, and they in turn attract predators.

Piping plovers are beach specialists and nest on the beach, which is why they are endangered. They are called piping because of their high-pitched whistle. They are seen singly on the beach and rest on the upper beach and the beginning of dunes. They arrive in April. Males make small scrapes in the sand and females lay their eggs (usually four) directly in the sand. The female and male incubate the eggs together for 28 days. Heat is a large concern for eggs. The chicks are born precocious and hit the ground running; within four weeks of hatching, they can fly. The beach provides enough food to raise them. Piping plovers do not mate for life, but are philopatric and pair up with old partners. They will return to the scraping spot, if it was successful, the next year.

Adult defense is to distract or camouflage. Chicks freeze: oftentimes people will pick up the “frozen” chick. If you find a frozen chick leave it alone.

Protective fencing allows plovers to leave nests but excludes predators such as fox, raccoon, and dogs. In ’02 there were 66 nesting pairs in Maine—it decreased to 33 by 2011. Fencing enclosures have been essential to increasing plover populations. In MA and NY they have a greater piping plover population because they have more sandy beach.

A “dirty” beach is a healthy beach. People don’t like the wrack line of seaweed on the beach and it is often swept away; however, wrack helps build dunes, and increases moisture content on the beach. Little arthropods live in there. During migration season you can see the wrack line move (from the birds taking off). In natural beach areas were there is no grooming you can see over time how the sand builds up.

The group watched a common tern and cormorant forage off of the beach. The common tern dive bombs into the water. Common terns nest on islands. Migratory shorebirds have to fatten up on the shorelines of Maine and New Brunswick before their two-day direct flight to South America.

Piping plovers are specialists and gulls (don’t say seagulls!) are generalists.

Common birds to see at the beach:

Greater black-backed gull is Maine’s largest gull.

Herring gull is the most common, grey-black gull with a bright yellow bill.

Ring-billed gull is smaller than the herring gull.

Laughing gull has a black head and red bill; they are nesting here more frequently.

Bonaparte’s gull doesn’t nest here, but passes through. They nest in trees, and forage like shorebirds by tapping with their feet and waiting for food to come to the surface.

Cormorants are fish eaters; they lack the oil gland so they are often seen drying their wings in the sun.

Least tern, the smallest tern, is a specialist, colonial waterbird that forages offshore. There are three nesting sites in Maine. Males have a white stripe by the eye and yellow bill. Call is a high-pitched squeak.

Common eiders inhabit the rock line, offshore and exhibit “creche behavior”: multiple females defend a large group of chicks, even females that have lost young will help defend rocky areas.

Short-eared owls forage for rodents on the beach.

— by Annie Cox