This Bird Finds Fish Without Seeing Them

[00:00:00]The water gives almost nothing away.

[00:00:02]A small fish moves just beneath the surface.

[00:00:06]Above it, a bird flies so low that its wings nearly touch the water.

[00:00:12]Its bill is open.

[00:00:14]The lower half cuts into the surface like a narrow blade.

[00:00:18]Then a fish touches the submerged lower jaw.

[00:00:22]The bird's head moves down and back.

[00:00:26]Its jaws close.

[00:00:28]A fish rises from the dark water.

[00:00:32]This is the black skimmer.

[00:00:34]Its black back and white body make it easy to recognize, but its most unusual feature is the bill.

[00:00:42]The lower jaw is much longer than the upper jaw.

[00:00:46]It may look unbalanced when the bird is standing on a beach.

[00:00:49]In flight, that shape begins to make sense.

[00:00:53]The skimmer lowers itself until it is only a short distance above the water.

[00:00:58]It opens its bill before the lower jaw enters the surface. The upper jaw usually remains above the water.

[00:01:06]The lower jaw continues forward beneath it.

[00:01:10]The bird does not need to see a fish before beginning the catch.

[00:01:14]Instead, it waits for contact.

[00:01:18]When a fish touches the lower jaw, the neck gives and the head moves downward and backward.

[00:01:26]The upper jaw comes down as the jaws close around the prey.

[00:01:30]The fish is pulled from the water.

[00:01:33]Every part of this movement has a role.

[00:01:36]The long lower jaw reaches through the water. Its narrow streamlined shape keeps water resistance relatively low during a straight pass.

[00:01:46]The shorter upper jaw stays clear of the surface during much of the hunting pass.

[00:01:52]Then the movement of the head brings the prey within reach of both jaws.

[00:01:57]That movement also cushions the sudden resistance of the fish.

[00:02:01]This movement reduces the force passed through the bill and neck.

[00:02:06]The skimmer does not simply carry an unusual bill.

[00:02:09]Its head, jaws, neck, and flight all work as one system.

[00:02:16]Touch begins the catch.

[00:02:19]Movement completes it.

[00:02:21]This feeding method is known as skimming.

[00:02:24]Only three living bird species use it in this specialized way.

[00:02:29]All three belong to the skimmer group.

[00:02:32]The black skimmer is the only one found in the Americas.

[00:02:37]Its feeding style changes the meaning of darkness.

[00:02:41]Many hunting birds depend heavily on sight.

[00:02:45]The skimmer can begin its final response through touch.

[00:02:49]It can feed during daylight. It can also hunt around dawn and dusk.

[00:02:54]It may continue well into the night.

[00:02:58]Calm water can make the narrow hunting path easier to hold.

[00:03:03]In some places, small fish may also be closer to the surface at these times.

[00:03:09]The skimmer passes through this narrow space between air and water.

[00:03:14]Its wings remain above. Its lower jaw moves below.

[00:03:19]For a few seconds, one bird is working in two different worlds.

[00:03:24]The adult bill seems perfectly shaped for this life, but a black skimmer does not hatch with it.

[00:03:31]A new chick has an upper and lower jaw of nearly equal length.

[00:03:36]At this age, the chick is not yet hunting over open water.

[00:03:40]It remains on the sand near the nesting colony.

[00:03:44]Its parents bring fish back from their feeding grounds.

[00:03:48]A meal may be offered directly or dropped where the chick can pick it up.

[00:03:53]Two jaws of similar length help the young bird handle food on the ground.

[00:03:58]The chick's first bill fits the life it is living now.

[00:04:03]Then, the proportions begin to change.

[00:04:06]The lower jaw grows farther beyond the upper jaw.

[00:04:10]By the time the young skimmer is ready to fly at about 4 weeks of age, the lower jaw may already extend nearly half an inch beyond the upper.

[00:04:20]The bill has not simply grown larger.

[00:04:23]Its working shape has appeared.

[00:04:26]The change prepares the young bird for a different way of finding food.

[00:04:32]First, the chick waits on the beach.

[00:04:35]Later, it must fly low above moving water.

[00:04:39]First, food arrives from a parent.

[00:04:43]Later, the bird must detect prey through its own bill.

[00:04:48]Growth connects these two lives.

[00:04:51]The young skimmer does not become an expert >> [music] >> immediately.

[00:04:55]Soon after its first flights, it begins to practice.

[00:04:58]A juvenile may lower its bill toward the water and attempt short skimming passes.

[00:05:04]Some attempts find nothing.

[00:05:07]The timing is still developing.

[00:05:09]The flight must remain steady.

[00:05:11]The lower jaw must enter the water at the correct angle.

[00:05:16]The bird must react quickly when contact comes.

[00:05:20]Through practice, [music] the growing bill and the flight response begin to work together.

[00:05:26]The beach is still close. Adult birds may be nearby, but the young skimmer has begun to search for its own meals.

[00:05:35]The adult hunting system depends on balance.

[00:05:38]Flying too high would lift the lower jaw from the water.

[00:05:42]Flying too low could bring the body or wings into contact with the surface.

[00:05:48]The bill must remain open during the searching phase.

[00:05:52]The neck must respond when something is struck.

[00:05:55]The jaws must close before the prey escapes.

[00:06:00]A successful pass may last only a few seconds.

[00:06:03]Inside those seconds is a precise chain of events.

[00:06:08]Low flight creates the path.

[00:06:11]The lower jaw searches beneath the surface. Contact sends the signal.

[00:06:16]The head moves down and back. The jaws close.

[00:06:20]The fish leaves the water.

[00:06:23]The skimmer may repeat this movement again and again.

[00:06:27]It often feeds over sheltered bays, lagoons, estuaries, tidal pools, and other areas with relatively smooth water.

[00:06:37]Nearby beaches and sandbars provide places to rest.

[00:06:41]They also provide open ground for nesting colonies.

[00:06:45]The water supports the adults.

[00:06:47]The sand holds the next generation.

[00:06:51]At first, the black skimmer's bill may seem like an extreme design. But the bird's life reveals its purpose.

[00:06:59]The extra length is not decoration. It is the first point of contact with hidden prey.

[00:07:06]The flexible response of the neck is not a separate trick. It helps turn a sudden strike into a controlled catch.

[00:07:13]Even the chick's balanced bill has its own moment of usefulness.

[00:07:18]One form helps the young bird eat on land.

[00:07:22]>> [music] >> Another form helps the growing bird hunt over water.

[00:07:26]Evening settles across a quiet bay.

[00:07:29]The bright surface slowly loses its color.

[00:07:32]A black skimmer rises from the sand.

[00:07:35]>> [music] >> Its long wings carry it toward the open water.

[00:07:40]The bird descends. Its bill opens.

[00:07:43]The lower jaw meets the surface and draws a thin line through it.

[00:07:49]For a moment, nothing happens.

[00:07:51]Then, there is contact.

[00:07:54]The head moves. The bill closes.

[00:07:57]The skimmer rises with a small fish.

[00:08:01]Farther along the shore, a young bird stands beside the colony.

[00:08:05]Its lower jaw is still growing.

[00:08:08]Soon, [music] it too will leave the sand and follow that narrow path above the water.

[00:08:15]The tide continues beneath the fading sky and another quiet hunting pass begins.

[00:08:23]Nature speaks. We translate.