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- Permanent Link:
- http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI14090843/00001
Notes
- Scope and Content:
- Source: Least Terns 1
Length of Segment: 00:01:11
Hi, I'm Dr. Jerry Jackson, out with the wild things. Terns are members of the same family that includes gulls, but terns differ from gulls in important ways. Gulls are scavengers and predators that capture what they can on water or land by grabbing it, but gulls don't dive. Terns are fish-eating predators that hover briefly above water and dive in to capture prey. They also take other small animals even over land, but always by diving. Gulls often rest floating on the water; terns never do. Both gulls and terns can be seen loafing on the beach and their appearance allows us to distinguish them. A gull stands upright with a rounded head and a heavy bill that is not sharply pointed. A tern is more sleek, almost seeming to hug the ground on its short legs. A tern often has a crest that seems slicked back and has a bill that is straight, dagger-like, and sharply pointed. A gull's large wings and short broad tail allow it to sometimes sail with little effort on coastal breezes. A tern's wings are long, narrow, and pointed, perfect for speed and maneuvering, and its often forked tail allows intricate control of every dive. ( English )
- Scope and Content:
- Source: Least Terns 2
Length of Segment: 00:01:16
Hi, I'm Dr. Jerry Jackson, out with the wild things. Although only a little over eight inches long, the least tern is a master traveler, winging its way in small flocks twice a year between its breeding sites in North America and wintering areas off the northeast coast of South America. Least terns arrive in Florida in April and most leave by mid-October. Each year, least terns seek out open beaches or beach-like habitats as nesting colony sites and begin their annual courtship flights nearby. Males test the waters for availability of the tiny fishes they eat and attract a mate by demonstrating their fishing abilities. During April and May, male least terns are often seen carrying tiny fishes in their bill as they pursue a second bird. Although males and females look alike, they seem to know the difference. The male is in pursuit of a mate in what is known as his 'fish flight'. If she's interested, she lands and he joins her. She holds her head high as he dances around her, fish in bill. If she's still interested, she crouches down and he steps onto her back, dangling the fish in front of her. If she seizes the fish, he mates with her, and a pair-bond is formed. If not, the male resumes his search. ( English )
- Scope and Content:
- Source: Least Terns 3
Length of Segment: 00:01:15
Hi, I'm Dr. Jerry Jackson, out with the wild things. Least terns can be found in coastal areas and along major rivers through much of North America, although for more than a century their numbers have been declining. Populations in Florida are listed as threatened. In the late-1800s, these tiny, fork-tailed, gray and white birds with a crisp black cap and striking dagger-like black-tipped yellow bill were shot by the thousands and skinned to become ornaments on ladies' hats. Such slaughter led to conservation movements, changes in fashion, and laws that protected birds but not their habitat. Although tern populations rebounded, popularity of recreation on beaches led to disturbances of nesting colonies that resulted in further losses. Damming and channelization of rivers eliminated sand bars where inland least terns nested. Pollutants ranging from pesticides to silt from construction reduced tern food resources. Efforts are now made to protect Florida's least tern nesting areas. Please stay out of tern nesting areas. Birds disturbed from their nests for only a few minutes can result in eggs and chicks that die in the Florida sun. A future for the least tern depends on all of us. ( English )
- Scope and Content:
- Source: Least Terns 4
Length of Segment: 00:01:10
Hi, I'm Dr. Jerry Jackson, out with the wild things. Least terns are sea birds that nest only in very open areas, and they prefer open beaches. Under natural conditions, these habitats are occasionally flooded by storm surges and if they're not, beach vegetation takes them over. The choice for the birds is a tricky one: selection of a site that is too low could mean a loss of the nest later due to flooding. Selection of a site with too much vegetation may result in increased losses of nests and adults to predators. Under natural conditions, least terns nest in colonies of ten to twenty pairs, the numbers providing some protection against potential predators. Colony sites naturally change from year to year as habitats change. The typical small colony size and shifting of colony sites may be important to the survival of these birds. While a predator that finds a colony site may destroy all of the nests, the colony isn't large enough to sustain a predator population over time. By shifting the colony site from year to year, predators must discover it anew each season. ( English )
- Scope and Content:
- Source: Least Terns 5
Length of Segment: 00:01:15
Hi, I'm Dr. Jerry Jackson, out with the wild things. As Florida's beaches have become increasingly used by humans, least terns must look elsewhere for nest sites. One habitat used by nesting least terns across the state is flat graveled rooftops. Pea gravel on some rooftops provides a habitat much like an open beach. On rooftops, terns have little disturbance from humans and predators. They've been successful enough that the birds return year after year. Rooftop nesting does have its own set of problems. Under the gravel, there's usually a layer of tar and in the heat of the summer, the tar gets sticky and gives off toxic fumes. The best roofs for tern nesting have a wall around the edge that prevents chicks from falling off and provides a bit of shade. Air-conditioning units on rooftops produce puddles in which both chicks and adults drink and bathe, but because of the wall, the surface is not cooled by breezes and temperatures can exceed 140 degrees. Adults have to work to keep eggs cool rather than to keep them warm. They soak breast feathers in water, then return to drip onto the nest. Tern chicks on rooftops often have badly burned feet; this tar beach is no substitute for the real thing. ( English )
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- Resource Identifier:
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