1 00:00:00,050 --> 00:00:02,290 A KQED HD production. 2 00:00:05,710 --> 00:00:22,399 It starts with a distant call. 3 00:00:22,859 --> 00:00:25,859 An ancient song heard through the rising mist 4 00:00:25,859 --> 00:00:28,140 announcing the changing of the seasons. 5 00:00:31,179 --> 00:00:33,920 For thousands of years and countless generations, 6 00:00:34,259 --> 00:00:37,719 they have flown this path, arriving, then departing, 7 00:00:38,060 --> 00:00:41,119 providing a rhythmic pulse to the natural world. 8 00:00:42,240 --> 00:00:45,299 People's connection with birds and their migrations 9 00:00:45,299 --> 00:00:47,700 goes back thousands of years. 10 00:00:47,899 --> 00:00:52,960 Aristotle commented on that, and they speculated on bird migrations. 11 00:00:53,200 --> 00:00:58,880 They definitely use bird migration as a timer for their seasons. 12 00:00:59,280 --> 00:01:02,100 The robins showing up in your backyard and singing. 13 00:01:02,759 --> 00:01:04,859 The geese that show up in the fall. 14 00:01:08,040 --> 00:01:11,040 Today, scientists working in California's Central Valley 15 00:01:11,040 --> 00:01:15,420 are finding important links between bird migration and global changes, 16 00:01:15,420 --> 00:01:17,519 both natural and man-made. 17 00:01:17,640 --> 00:01:25,870 Understanding how birds use their environment and the routes they fly 18 00:01:25,870 --> 00:01:28,870 will help conservationists preserve and protect habitat. 19 00:01:28,870 --> 00:01:33,870 The information that we're getting from understanding bird migration 20 00:01:33,870 --> 00:01:37,870 is a really powerful tool for us from an applied conservation perspective. 21 00:01:37,870 --> 00:01:41,870 Some of these birds are going from one end of the globe to the other, 22 00:01:41,870 --> 00:01:46,870 and we have limited conservation funds, limited resources, 23 00:01:46,870 --> 00:01:51,049 And so it allows us really to hone in on the key sites 24 00:01:51,049 --> 00:01:54,849 that are important to different migratory animals 25 00:01:54,849 --> 00:02:01,769 and to dedicate our resources to those priority areas. 26 00:02:01,769 --> 00:02:05,450 It's long been known that migrating birds follow the wings 27 00:02:05,450 --> 00:02:09,530 of their ancestors and use the same age-old flight paths. 28 00:02:09,530 --> 00:02:14,509 Scientists call these well-traveled routes flyways. 29 00:02:14,509 --> 00:02:17,849 The whole flyway concept was developed in the 1930s 30 00:02:17,849 --> 00:02:21,689 by a guy, Frederick Lincoln, who, he was looking at band 31 00:02:21,689 --> 00:02:26,349 recoveries of waterfowl, ducks and geese, and he found that 32 00:02:26,349 --> 00:02:29,590 birds were using these predictable corridors through 33 00:02:29,590 --> 00:02:33,189 the United States. And he defined four corridors, which 34 00:02:33,189 --> 00:02:37,409 he called flyways, the Pacific, the Central and Mississippi 35 00:02:37,409 --> 00:02:41,789 flyways, and then the Atlantic flyway. 36 00:02:41,789 --> 00:02:44,830 Up to 13 different flyways have been identified 37 00:02:44,830 --> 00:02:48,389 around the world. The Pacific flyway runs from the Arctic 38 00:02:48,389 --> 00:02:54,449 circle to the tip of South America. Millions of birds from more than 300 different species 39 00:02:54,449 --> 00:03:00,650 make an annual journey up and down the Pacific Corridor, taking advantage of the best habitat 40 00:03:00,650 --> 00:03:07,050 conditions for breeding and foraging for food. The flyway in and of itself is a really interesting 41 00:03:07,050 --> 00:03:12,530 thing from an evolutionary perspective. You might wonder why birds would travel such long distances 42 00:03:12,530 --> 00:03:15,870 And it turns out it's actually more energy efficient. 43 00:03:16,629 --> 00:03:22,870 They migrate up to the north to capture the longer hours during the northern summer. 44 00:03:23,430 --> 00:03:29,030 So because it's daylight for a much longer period, they're able to forage for a longer period. 45 00:03:29,490 --> 00:03:38,569 And that helps them to be more successful in nesting and also having larger numbers of eggs that successfully hatch. 46 00:03:39,530 --> 00:03:44,169 And as those conditions change and the day length shortens, 47 00:03:44,729 --> 00:03:49,490 they migrate back down to the southern regions that are more hospitable to overwinter. 48 00:03:51,310 --> 00:03:54,409 No two species follow the same exact route. 49 00:03:54,409 --> 00:03:58,490 Some fly thousands of miles, some just a short distance, 50 00:03:58,830 --> 00:04:02,530 many crossing paths in the San Francisco Bay and the Delta. 51 00:04:03,310 --> 00:04:06,669 This is essential habitat for these long-distance travelers. 52 00:04:06,669 --> 00:04:09,669 For some birds, it's their final destination. 53 00:04:09,669 --> 00:04:12,669 For others, a crucial rest stop 54 00:04:12,669 --> 00:04:15,669 as they make the trek further south. 55 00:04:15,669 --> 00:04:18,670 You might even call the San Francisco Bay Area 56 00:04:18,670 --> 00:04:21,670 the grand central station for birds on the Pacific Flyway. 57 00:04:21,670 --> 00:04:23,670 It's really the meeting point 58 00:04:23,670 --> 00:04:25,670 for so many different bird species. 59 00:04:25,670 --> 00:04:28,670 We have your waterfowl that come down from the north. 60 00:04:28,670 --> 00:04:31,670 We have smaller species like songbird. 61 00:04:31,670 --> 00:04:33,670 We have raptors that fly through. 62 00:04:33,670 --> 00:04:38,550 And it's really just such a great mixing bowl for all of these different species. 63 00:04:41,639 --> 00:04:44,220 How birds navigate is still somewhat of a mystery. 64 00:04:45,000 --> 00:04:46,980 Some are genetically hardwired. 65 00:04:47,420 --> 00:04:51,199 Many use the sun, the stars, and landscape to guide them, 66 00:04:51,560 --> 00:04:54,800 while others are in tune with the Earth's magnetic poles. 67 00:04:57,860 --> 00:05:00,839 We don't fully understand how birds migrate 68 00:05:00,839 --> 00:05:05,579 and what might be their triggers for landing in the exact same place year to year. 69 00:05:05,579 --> 00:05:10,060 but it is true that you can put up a net in the same place year to year 70 00:05:10,060 --> 00:05:12,899 and catch the same identical bird. 71 00:05:14,379 --> 00:05:18,759 Biologist Cheryl Strong and her team from the U.S. Fish and Wildlife Service 72 00:05:18,759 --> 00:05:24,420 are banding songbirds at the Don Edwards Wildlife Refuge near Newark, California. 73 00:05:25,100 --> 00:05:29,980 So this guy's band is 0-1-7-0-1. 74 00:05:30,740 --> 00:05:34,139 Once they're banded, if they're recaptured somewhere else, 75 00:05:34,139 --> 00:05:36,639 then you get a lot of information about the movement of those birds. 76 00:05:36,759 --> 00:05:40,199 You can also get information on survival and lifespan of those birds 77 00:05:40,199 --> 00:05:41,660 and also behavior of the birds. 78 00:05:44,170 --> 00:05:47,509 Joe has a hermit thrush, which is a bird that winters here. 79 00:05:49,069 --> 00:05:54,529 It's actually really rare to know exactly where the same population of birds winters 80 00:05:54,529 --> 00:05:58,230 and also breeds, so if you can get that kind of information, 81 00:05:58,370 --> 00:05:59,850 it's really valuable to see. 82 00:05:59,990 --> 00:06:04,629 If you have a declining species, such as a songbird or even a duck, 83 00:06:04,629 --> 00:06:11,290 If you know what the threats are to that bird, either on its breeding grounds or on its wintering grounds, 84 00:06:11,350 --> 00:06:13,069 then you can better help conserve that bird. 85 00:06:14,029 --> 00:06:14,649 And there he goes. 86 00:06:17,170 --> 00:06:25,050 Biologists are now concerned with reports that the majority of migrating songbird species are suffering population declines. 87 00:06:26,149 --> 00:06:34,470 Another report by the U.S. Department of Interior indicates half of America's migrating coastal shorebird species are in decline. 88 00:06:35,449 --> 00:06:38,829 While population numbers of waterfowl vary from year to year, 89 00:06:39,069 --> 00:06:42,110 many species of ducks and geese are faring better. 90 00:06:43,089 --> 00:06:46,009 Birds face many threats along the Pacific Flyway, 91 00:06:46,009 --> 00:06:48,329 from pollution to habitat loss. 92 00:06:50,029 --> 00:06:56,720 To get a more comprehensive view of exactly where the birds go 93 00:06:56,720 --> 00:06:58,959 and what they face on their migration, 94 00:06:59,519 --> 00:07:04,199 scientists are employing sophisticated radio and satellite tracking devices. 95 00:07:05,180 --> 00:07:08,139 There's several ways you can track a migratory bird. 96 00:07:08,300 --> 00:07:11,860 One way is using satellite transmitters, 97 00:07:12,019 --> 00:07:17,680 which this is a 12-gram satellite transmitter that attaches to a bird's back. 98 00:07:18,759 --> 00:07:24,879 Powered by a solar cell, the device can send information via satellite for months, even years, 99 00:07:24,879 --> 00:07:29,579 providing scientists a way to actively follow individual birds. 100 00:07:32,529 --> 00:07:37,370 Last summer, biologists trapped and satellite-tagged long-billed curlews 101 00:07:37,370 --> 00:07:40,089 on their nesting grounds in the prairies of Montana. 102 00:07:42,870 --> 00:07:46,670 The long-billed curlew is the largest shorebird in North America. 103 00:07:47,569 --> 00:07:51,850 And it breeds in the prairies and in the Great Basin. 104 00:07:51,850 --> 00:07:55,250 And then it migrates 600 to 1,200 miles south. 105 00:07:55,990 --> 00:07:59,850 And a lot of them come to the Central Valley of California. 106 00:07:59,850 --> 00:08:08,110 And we became very interested in how important is the Central Valley for the wintering long-billed curlews. 107 00:08:08,509 --> 00:08:14,250 We found the curlews very dependent on agricultural lands, and particularly they like alfalfa. 108 00:08:16,129 --> 00:08:23,790 Biologists released the curlews in Montana and have tracked them as they've traveled down to their winter home west of Sacramento. 109 00:08:24,449 --> 00:08:30,269 We've had about 10 long-billed curlers in the valley that we've monitored over the past three years. 110 00:08:30,949 --> 00:08:35,570 And we found, interestingly, they're very sight-faithful from one year to the next. 111 00:08:37,110 --> 00:08:41,549 There's concern about the curlers because they're so dependent on man-made habitats 112 00:08:41,549 --> 00:08:43,409 much more than a lot of other species. 113 00:08:44,730 --> 00:08:50,169 Changes in habitat or climate can impact and disrupt the rhythm of migration. 114 00:08:50,169 --> 00:09:01,669 In 2009, a National Audubon Society study found that more than 150 species of migratory birds are wintering further north than they were 40 years ago. 115 00:09:02,009 --> 00:09:09,889 There's a lot of talk lately about migration phenology, which is basically the timing of migration based on what's happening in the environment. 116 00:09:10,590 --> 00:09:14,230 And the chance of that will change because of climate change. 117 00:09:14,230 --> 00:09:21,350 So the cues that birds use to migrate are changing, and it might make them migrate too soon or too late. 118 00:09:21,929 --> 00:09:26,509 And the danger is that they could arrive to the breeding ground at the wrong time. 119 00:09:30,460 --> 00:09:37,460 Migratory birds are the proverbial canary in the coal mine, a warning signal of the failing health of our ecosystems. 120 00:09:38,299 --> 00:09:43,919 Small shifts in their patterns are telling us that the rhythm of the natural world is changing. 121 00:09:43,919 --> 00:09:48,919 and those environmental changes will affect all life on this planet. 122 00:09:48,919 --> 00:09:52,919 I think it's valuable to study birds. 123 00:09:52,919 --> 00:09:57,919 They're one of the best interfaces between man and the environment. 124 00:09:57,919 --> 00:10:01,919 The real ability of birds and all the different things they do 125 00:10:01,919 --> 00:10:05,919 needs to be appreciated by the public so they want to conserve them. 126 00:10:05,919 --> 00:10:10,759 The reason I study birds is because I want to preserve the beauty of the Earth.