1 00:00:15,483 --> 00:00:30,034 [Upbeat Jazz 2 00:00:30,034 --> 00:00:37,300 Trumpet] 3 00:00:37,300 --> 00:00:44,567 Water. 4 00:00:45,117 --> 00:00:46,684 We take it for granted. 5 00:00:46,684 --> 00:00:49,251 But all life depends on water. 6 00:00:49,251 --> 00:00:52,618 Water is one of the more stable molecules known to chemistry. 7 00:00:53,401 --> 00:00:55,551 The water present in the biosphere today 8 00:00:55,768 --> 00:00:58,801 is the same water that has been here through geological time. 9 00:00:59,401 --> 00:01:02,101 Moving from place to place, passing through the bodies 10 00:01:02,101 --> 00:01:05,035 of plants and animals, evaporating into clouds, 11 00:01:05,401 --> 00:01:09,568 only to fall back on the earth again, shaping the contours of the land 12 00:01:09,568 --> 00:01:12,118 as it flows back down to the sea from whence it came. 13 00:01:13,835 --> 00:01:16,235 Life originated in water. 14 00:01:16,235 --> 00:01:20,035 Most of the bodies of all living animals, including humans, is water. 15 00:01:20,852 --> 00:01:23,185 All animals need water to survive, 16 00:01:23,452 --> 00:01:26,002 even though some never drink water directly. 17 00:01:26,852 --> 00:01:30,935 This program is about birds whose lives are spent close to the water. 18 00:01:31,435 --> 00:01:33,752 The water birds. 19 00:01:37,535 --> 00:01:39,002 Most taxonomists 20 00:01:39,002 --> 00:01:41,969 classify the birds of the world in 26 orders. 21 00:01:42,686 --> 00:01:45,336 The species within each order are believed 22 00:01:45,336 --> 00:01:47,669 to have evolved from a common ancestor. 23 00:01:48,486 --> 00:01:50,936 Several of the orders consist of birds 24 00:01:50,936 --> 00:01:53,636 whose lives are very closely tied to the water. 25 00:01:55,286 --> 00:01:59,453 An example of the order of waterbirds that we believe is the most primitive 26 00:01:59,669 --> 00:02:02,753 and therefore the oldest is the common loon. 27 00:02:03,503 --> 00:02:08,220 Loons are large birds which capture fish by diving below the surface of the water. 28 00:02:08,853 --> 00:02:12,353 They are seldom very far from water throughout their lifecycle. 29 00:02:12,753 --> 00:02:14,970 Even laying eggs in a floating nest. 30 00:02:15,920 --> 00:02:19,320 They are good underwater swimmers and great fliers 31 00:02:19,736 --> 00:02:23,337 capable of performing long migratory flights from their northern 32 00:02:23,337 --> 00:02:26,637 nesting grounds to the southern estuaries where they winter 33 00:02:27,503 --> 00:02:30,120 rails belong to another order of water birds. 34 00:02:30,620 --> 00:02:33,270 They are a compact kin like marsh birds 35 00:02:33,387 --> 00:02:35,704 with secretive habits and mysterious voices. 36 00:02:36,354 --> 00:02:38,937 The clapper rails pictured here are seldom 37 00:02:38,937 --> 00:02:41,554 seen outside of the protective covering of marshes. 38 00:02:42,170 --> 00:02:42,720 Their dagger 39 00:02:42,720 --> 00:02:46,587 like movement is both quick and effective when hunting at the marsh edge. 40 00:02:47,304 --> 00:02:52,254 These rails do not appear to be strong fliers, but all rails are great wanderers. 41 00:02:52,654 --> 00:02:55,354 They are year round residents of the coastal marshes of 42 00:02:55,354 --> 00:02:58,654 North and South America. 43 00:03:00,304 --> 00:03:01,471 Unlike the diving 44 00:03:01,471 --> 00:03:04,971 loons and the secretive rails, herons are wading birds. 45 00:03:05,454 --> 00:03:07,654 They hunt fish generally by stalking 46 00:03:08,271 --> 00:03:11,221 and striking with lightning, fast jabs with their bill. 47 00:03:12,021 --> 00:03:16,555 This great blue heron eats not only fish but snakes, frogs, lizards, 48 00:03:16,705 --> 00:03:19,971 small mammals in generally anything else that moves. 49 00:03:20,555 --> 00:03:25,055 Not surprisingly, the great blue heron is the most widely dispersed species 50 00:03:25,055 --> 00:03:27,655 apparent in North America. 51 00:03:29,572 --> 00:03:32,672 The pelicans and their allies form a different order. 52 00:03:33,272 --> 00:03:37,322 This brown pelican feeds by plunging into the water from high in the air. 53 00:03:38,005 --> 00:03:40,672 When the bird hits the water, the huge pouch 54 00:03:40,672 --> 00:03:43,522 expands and acts like a bag to catch the fish. 55 00:03:44,155 --> 00:03:48,389 The pelican then surfaces, expels the water and swallows the fish. 56 00:03:49,439 --> 00:03:52,106 Not all of the members of this order look like pelicans, 57 00:03:52,289 --> 00:03:54,089 nor do they fish like pelicans. 58 00:03:55,372 --> 00:03:56,572 This double crested 59 00:03:56,572 --> 00:04:00,456 cormorant dives from the surface to catch fish, just as a loon does. 60 00:04:00,689 --> 00:04:03,322 Rather than plunging into the water from high in the air, 61 00:04:04,256 --> 00:04:07,289 Why, then, is the cormorant placed in the order with the pelicans 62 00:04:07,289 --> 00:04:09,439 rather than with, say, the loons? 63 00:04:09,439 --> 00:04:12,089 The reason is that the classification scheme reflects 64 00:04:12,089 --> 00:04:16,256 evolutionary relationships rather than behavioral similarities. 65 00:04:16,623 --> 00:04:18,390 One of the most important characteristics 66 00:04:18,390 --> 00:04:21,540 that pelicans and cormorants have in common is that all four 67 00:04:21,540 --> 00:04:25,006 toes are webbed in all other web footed orders of birds. 68 00:04:25,023 --> 00:04:27,640 Only three toes are with the fourth toe. 69 00:04:27,723 --> 00:04:30,423 If present at all is separated from the webbing, 70 00:04:30,807 --> 00:04:34,557 all the ducks have webbed feet, but only three toes are webbed. 71 00:04:35,040 --> 00:04:39,123 This mallard duck is a good example of the order, which includes geese and swans. 72 00:04:41,040 --> 00:04:41,973 Birds in this 73 00:04:41,973 --> 00:04:45,240 order have bills which are unlike the bills of any other birds. 74 00:04:45,240 --> 00:04:46,624 We have seen. 75 00:04:46,740 --> 00:04:51,274 Many ducks are vegetarians, and humans find them particularly palatable. 76 00:04:51,924 --> 00:04:54,774 Some ducks eat mollusks 77 00:04:54,774 --> 00:04:57,357 and there is one group of fish eating ducks. 78 00:04:57,774 --> 00:04:59,824 The mergansers. 79 00:04:59,991 --> 00:05:04,441 the inner surfaces of the bills of red breasted mergansers are much like saws. 80 00:05:04,707 --> 00:05:07,791 Indeed, hunters call them saw bills. 81 00:05:07,791 --> 00:05:12,324 The rough surface bill helps the bird grasp slippery, struggling fish. 82 00:05:14,241 --> 00:05:15,874 The largest and most varied 83 00:05:15,874 --> 00:05:18,691 order of waterbirds is this charade reforms. 84 00:05:19,224 --> 00:05:23,491 This order includes Sandpipers, such as this sanderlin and gulls. 85 00:05:24,058 --> 00:05:26,941 This ring billed gull doesn't look much like a sanderlin, 86 00:05:27,275 --> 00:05:29,608 but it shares many internal characteristics. 87 00:05:30,241 --> 00:05:34,042 On the basis of these shared characteristics, taxonomists 88 00:05:34,042 --> 00:05:38,342 believe that gulls and sandpipers are descended from a common ancestor. 89 00:05:38,642 --> 00:05:41,008 Thus they are placed in the same order. 90 00:05:42,775 --> 00:05:43,442 Birds are 91 00:05:43,442 --> 00:05:46,675 perhaps the most vividly colored of all higher life forms. 92 00:05:47,225 --> 00:05:50,975 Birds have well-developed color vision equal to that of primates. 93 00:05:51,575 --> 00:05:55,325 Color serve as signals to others of their kind in several different ways. 94 00:05:55,892 --> 00:05:59,159 Among many of the waterbirds, plumage varies with the season. 95 00:05:59,492 --> 00:06:04,776 In the winter, this black bellied clover has a rather dull, gray basic plumage. 96 00:06:05,342 --> 00:06:10,109 It is not very conspicuous, and its coloration could even be called cryptic. 97 00:06:10,942 --> 00:06:13,326 Cryptic coloration is for concealment. 98 00:06:14,393 --> 00:06:18,893 When the breeding season approaches, the black bellied plover undergoes a molt. 99 00:06:19,459 --> 00:06:23,876 It sheds its old feathers and replaces them with new, more colorful ones. 100 00:06:24,359 --> 00:06:26,393 Its alternate plumage. 101 00:06:26,393 --> 00:06:29,093 Thus the bird signals to others that it is 102 00:06:29,093 --> 00:06:31,493 in breeding condition 103 00:06:33,260 --> 00:06:34,460 not only feathers, 104 00:06:34,460 --> 00:06:36,860 but the soft body parts may change as well. 105 00:06:37,443 --> 00:06:40,910 The bill of this laughing gull in basic plumage is black. 106 00:06:41,543 --> 00:06:43,760 But as the bird goes into alternate plumage, 107 00:06:43,977 --> 00:06:47,160 acquiring the full black head with the prominent white eye ring, 108 00:06:47,610 --> 00:06:52,027 the bill becomes red, signaling internal changes. 109 00:06:52,027 --> 00:06:55,677 Other optical signals important to waterbirds 110 00:06:55,910 --> 00:06:59,994 are those which indicate age or maturity among gulls. 111 00:07:00,177 --> 00:07:03,027 The onset of sexual maturity is somewhat delayed. 112 00:07:03,694 --> 00:07:07,144 Individuals of most species of gulls do not breed 113 00:07:07,144 --> 00:07:12,111 until they are about three years of age or in some species even older. 114 00:07:12,994 --> 00:07:15,861 Younger individuals such as this young herring gull 115 00:07:16,078 --> 00:07:19,411 have dull plumage and plain bills with dark tips. 116 00:07:20,244 --> 00:07:23,061 This adult herring gull has a gray mantle, 117 00:07:23,394 --> 00:07:26,844 a white head, and its bill has a well-defined yellow tip, 118 00:07:27,211 --> 00:07:30,661 a sure sign that this individual is old enough to nest. 119 00:07:31,461 --> 00:07:35,278 This immature brown pelican is uniformly colored, dull, gray. 120 00:07:35,811 --> 00:07:38,645 Notice that the breast and belly are lighter than the back. 121 00:07:39,261 --> 00:07:42,562 As the bird gets older, it molt into a different plumage. 122 00:07:43,345 --> 00:07:48,112 This adult brown pelican is dark on the breast and belly and has a light neck. 123 00:07:49,345 --> 00:07:51,928 When the brown pelican reaches its breeding stage, 124 00:07:52,262 --> 00:07:55,145 the back of its neck gets a rich chestnut brown 125 00:07:55,145 --> 00:07:57,262 that gives the species its name. 126 00:07:58,345 --> 00:08:00,512 Brown pelicans aren't really very brown. 127 00:08:00,995 --> 00:08:03,245 Most of the body is silver gray. 128 00:08:03,245 --> 00:08:06,395 The rich brown on the back of the neck is seen only on adult 129 00:08:06,395 --> 00:08:09,262 birds in breeding condition. 130 00:08:09,779 --> 00:08:11,012 A few years ago, 131 00:08:11,012 --> 00:08:14,962 the brown pelican population declined in most parts of its range 132 00:08:15,246 --> 00:08:19,262 because of the accumulation of pesticides in the environment. 133 00:08:19,529 --> 00:08:21,696 Pelicans are now staging a comeback 134 00:08:21,896 --> 00:08:24,663 because some damaging pesticides have been outlawed. 135 00:08:25,646 --> 00:08:29,963 Some birds remain inconspicuous as long as possible, but once seen, 136 00:08:30,213 --> 00:08:32,429 they want to become as visible as possible. 137 00:08:32,963 --> 00:08:36,146 The basic coloration of the willet is a dull gray, 138 00:08:36,563 --> 00:08:40,796 but when the willet flies, It exhibits a flashing black and white pattern, 139 00:08:40,980 --> 00:08:43,980 which is easily seen a mile or more away. 140 00:08:44,763 --> 00:08:47,063 The Willet is also highly vocal, 141 00:08:47,247 --> 00:08:51,063 giving a loud ringing call that further attracts attention to itself. 142 00:08:52,830 --> 00:08:53,613 A plausible 143 00:08:53,613 --> 00:08:56,613 explanation for this striking variation in visibility 144 00:08:56,997 --> 00:08:59,814 is that the bird is signaling a warning of danger. 145 00:09:00,530 --> 00:09:04,014 The principal advantage of its warning signal is to other willets. 146 00:09:04,497 --> 00:09:07,114 Though birds of many species doubtless depend 147 00:09:07,114 --> 00:09:09,747 on the willet to warn them that predators are about. 148 00:09:10,647 --> 00:09:13,231 This is an example of commensalism 149 00:09:13,414 --> 00:09:16,647 among water birds. 150 00:09:18,664 --> 00:09:20,031 Mutualism occurs 151 00:09:20,031 --> 00:09:24,331 when organisms of different species help each other to their mutual advantage. 152 00:09:24,931 --> 00:09:26,098 This snowy egret has 153 00:09:26,098 --> 00:09:29,364 sometimes been observed fishing with a double crested cormorant. 154 00:09:30,531 --> 00:09:35,164 The cormorant swims parallel to the path of the egret a few feet offshore. 155 00:09:35,631 --> 00:09:38,965 If the egret scares up a fish which tries to escape into deeper 156 00:09:38,965 --> 00:09:41,215 water, the cormorant may catch it. 157 00:09:42,081 --> 00:09:45,998 But if the fish sees the cormorant and turns back toward shore, 158 00:09:46,265 --> 00:09:49,948 the egret has another chance. 159 00:09:51,932 --> 00:09:53,815 Parasitism occurs when one 160 00:09:53,815 --> 00:09:56,815 species benefits to the detriment of another. 161 00:09:58,348 --> 00:09:59,998 Gulls seldom capture 162 00:09:59,998 --> 00:10:03,615 live fish, but if this least tern catches 163 00:10:03,632 --> 00:10:06,515 a fish by plunging into the water from high in the air. 164 00:10:07,415 --> 00:10:09,632 This ring billed gull may steal it. 165 00:10:10,582 --> 00:10:15,065 The gull will pursue the tern on the wing, twisting and turning as it tries 166 00:10:15,065 --> 00:10:20,132 to force the tern either to drop its prey or disgorge the contents of its stomach. 167 00:10:21,532 --> 00:10:25,649 Most water birds are predators, but gulls are scavengers, 168 00:10:26,182 --> 00:10:28,766 preferring to take dead or dying organisms 169 00:10:29,216 --> 00:10:31,616 rather than capturing live prey. 170 00:10:32,183 --> 00:10:36,799 Thus, gulls are prevalent at human garbage dumps, where food is abundant. 171 00:10:37,649 --> 00:10:39,866 Gulls are one of the few groups of birds 172 00:10:40,083 --> 00:10:42,116 that have benefited from human activity 173 00:10:43,350 --> 00:10:47,000 because gulls eat garbage and humans generate it. But 174 00:10:50,366 --> 00:10:53,850 other species of birds are declining. 175 00:10:53,850 --> 00:10:55,350 Researchers followed the habits 176 00:10:55,350 --> 00:10:59,250 and patterns of gulls closely to monitor diseases and maladies 177 00:10:59,450 --> 00:11:04,383 such as fowl pest, or nathosis intestinal parasites and food poisoning. 178 00:11:05,183 --> 00:11:09,384 Gulls habits are potentially dangerous if they commute from sewage farms 179 00:11:09,384 --> 00:11:13,734 and rubbish dumps to reservoirs or food markets to the present time. 180 00:11:14,034 --> 00:11:17,134 There have been no outbreaks of disease that have proved to be transmitted 181 00:11:17,134 --> 00:11:18,084 by gulls. 182 00:11:18,084 --> 00:11:22,251 To the contrary, gulls may perform a useful role by cleaning up garbage 183 00:11:22,384 --> 00:11:24,601 that somehow escapes mankind's control. 184 00:11:26,034 --> 00:11:29,034 All animals must compete for scarce resources, 185 00:11:29,434 --> 00:11:32,701 mainly food cover and breeding space. 186 00:11:33,801 --> 00:11:35,934 Waterbirds are no exception. 187 00:11:37,084 --> 00:11:40,018 There are many ways in which species have evolved 188 00:11:40,234 --> 00:11:42,868 to avoid competing directly with one another 189 00:11:43,134 --> 00:11:45,185 for precisely the same resource. 190 00:11:45,935 --> 00:11:48,118 Animals often partition resources 191 00:11:48,385 --> 00:11:52,051 to avoid direct competition. 192 00:11:53,885 --> 00:11:54,785 Many terns 193 00:11:54,785 --> 00:11:58,102 look much alike and fish in much the same way 194 00:11:58,535 --> 00:12:02,302 by plunging into the water in a steep dive from high in the air. 195 00:12:03,568 --> 00:12:06,352 This royal tern is a saltwater species 196 00:12:06,785 --> 00:12:09,785 and it is almost never seen away from the coast. 197 00:12:11,252 --> 00:12:13,502 Other terns, which look almost exactly 198 00:12:13,502 --> 00:12:18,452 like this one, such as the Caspian tern, are mainly freshwater species 199 00:12:18,685 --> 00:12:21,569 and nest on lakes in the interior of the continent. 200 00:12:22,919 --> 00:12:25,402 Thus, each species occupies 201 00:12:25,402 --> 00:12:28,402 a different ecological niche. 202 00:12:28,402 --> 00:12:31,769 Another way that birds partition resources is by size. 203 00:12:32,636 --> 00:12:36,152 This least tern is much smaller than either the Royal tern 204 00:12:36,152 --> 00:12:38,036 or the Caspian tern. 205 00:12:38,036 --> 00:12:40,469 The least tern preys on the smaller fish. 206 00:12:40,886 --> 00:12:44,853 The larger terns on the larger fish. 207 00:12:45,019 --> 00:12:49,053 Some of the best examples of partitioning are provided by Sandpipers. 208 00:12:49,703 --> 00:12:51,953 This sanderlin has light coloration. 209 00:12:52,353 --> 00:12:54,086 It is almost white. 210 00:12:54,086 --> 00:12:57,720 It should come as no surprise then, that the Sanderlin prefers to feed 211 00:12:57,720 --> 00:13:02,003 on the outer beaches where its pale coloration blends with the pale sand. 212 00:13:03,053 --> 00:13:03,687 Compared to the 213 00:13:03,687 --> 00:13:07,287 Sanderlin, a ruddy turnstone is several shades darker. 214 00:13:07,853 --> 00:13:11,120 The ruddy ternstone prefers to feed on nearby mudflats, 215 00:13:11,370 --> 00:13:13,853 where its darker coloration blends in. 216 00:13:14,453 --> 00:13:17,570 In contrast to the short bill of this piping plover, 217 00:13:18,004 --> 00:13:20,454 the bill of this willet is much longer. 218 00:13:21,004 --> 00:13:25,204 Obviously the plover is limited to food that it can pick up near the surface. 219 00:13:25,820 --> 00:13:29,554 While the willet can probe beneath the surface of mud or sand 220 00:13:29,904 --> 00:13:35,071 to capture invertebrates that live below the top layer. 221 00:13:35,071 --> 00:13:38,071 Notice also that the legs of the willet are longer, 222 00:13:38,371 --> 00:13:42,954 which permits this species of sandpiper to forage in deeper water. 223 00:13:43,954 --> 00:13:46,821 The least tern is a highly adaptable species 224 00:13:47,221 --> 00:13:51,171 capable of quickly taking advantage of changing ecological conditions 225 00:13:51,721 --> 00:13:54,321 beaches, sandbars and small islands. 226 00:13:54,505 --> 00:13:56,855 Shift and change with the wind and the tide. 227 00:13:57,388 --> 00:13:59,971 An area that provides excellent nesting habitat 228 00:13:59,971 --> 00:14:03,321 one year may be completely unusable the next. 229 00:14:04,888 --> 00:14:06,322 least terns often 230 00:14:06,322 --> 00:14:08,972 choose flat gravel roofs as nest sites. 231 00:14:09,422 --> 00:14:13,322 Obviously this nesting space did not exist when the species evolved, 232 00:14:13,888 --> 00:14:17,905 but gravel roofs resemble gravel or shale beaches closely enough 233 00:14:18,155 --> 00:14:22,555 that the birds are able to accept them as nesting places. 234 00:14:25,955 --> 00:14:28,472 Ultimately, the fate of all the waterbirds, 235 00:14:28,472 --> 00:14:33,172 like that of other life on this planet depends on humans like these birds. 236 00:14:33,356 --> 00:14:35,872 Humans, too, are attracted to water. 237 00:14:35,872 --> 00:14:38,939 Beaches are much in demand for recreation and home sites. 238 00:14:40,072 --> 00:14:44,522 Some species of birds, such as gulls and the least tern are able to adapt 239 00:14:44,522 --> 00:14:48,689 to human activities and can flourish in an environment altered by humans. 240 00:14:49,139 --> 00:14:50,823 Others cannot. 241 00:14:50,823 --> 00:14:55,073 The brown pelican and the piping plover are now classified as threatened 242 00:14:55,339 --> 00:14:57,540 because of human competition for the beaches, 243 00:14:57,723 --> 00:15:00,473 which are the birds preferred breeding sites. 244 00:15:00,473 --> 00:15:03,840 Humans ultimately must decide whether the water birds 245 00:15:03,840 --> 00:15:08,523 which grace this planet and so enrich our lives, will be allowed to survive. 246 00:15:09,440 --> 00:15:11,757 It is clearly up to us 247 00:15:11,757 --> 00:15:15,423 to find ways to partition our world with the water birds 248 00:15:16,023 --> 00:15:18,473 so we may continue to exist side 249 00:15:18,473 --> 00:15:56,824 by side.