Our Feathered Friends

Transcription

1 Exhibition Text Our Feathered Friends The exhibition text tells you exactly what the exhibition will say. It is divided according to what is written on the labels and panels of the exhibition. It is important that you read the text so that you understand the storyline (content) of the exhibition. This will also help you to start planning for the exhibition s installation and interpretation. PLEASE NOTE: The Canadian Museum of Nature s previous name (National Museum of Natural Sciences) still appears on all printed text panels in this exhibition.

2 Our Feathered Friends An introduction to birds and birdwatching A travelling exhibition from the National Museum of Natural Sciences What is a bird? Birds are found almost everywhere: from the Arctic to the Antarctic, in jungles and cities, from oceans to deserts. They range in size from the 125 kg Ostrich to the tiny Bee Hummingbird, which weighs less than 2g. Many are brightly coloured, but others are muted or dull. Most can fly, but some cannot. Some travel thousands of kilometres as they migrate north and south. Others remain close to home year-round. As diverse a group as they are, they all have one unique feature in common - feathers. Feathers Birds are the only animals that have feathers. Feathers probably evolved as a temperature control device from scales much like those of modern reptiles. They have since been adapted for many uses: to protect the body, provide insulation, promote flight and help in social communication. The shape and structure of feathers vary according to their function. Design for flight Only a few animals are capable of powered flight, but birds are the largest, fastest and most powerful. Flight makes enormous demands on a bird s body. Adaptations include a strong yet lightweight skeleton, powerful wings, a streamlined body and efficient metabolic and respiratory systems. A lightweight skeleton Birds have skeletons quite unlike those of other animals. The skeleton has evolved into a structure that combines tightness with strength. Thin, hollow bones, and bills instead of teeth and heavy jaws, help to minimize weight. Many of the bones are fused to strengthen the skeleton. One of the skeleton's most obvious features is a large keel which serves to anchor the well-developed wing muscles. How to identify birds Careful observation is the key to successful birdwatching. Shape, colour, voice and the habits of birds provide important clues to their identification. Begin by studying a few of the familiar birds in your neighbourhood. When you see a bird you cannot recognize, try answering the following questions. Page 2 of 11

3 Parts of a bird Backyard birds Observing birds in your backyard can be one of the best places to begin birdwatching. By creating a suitable habitat for our feathered friends, you can attract many species to your yard throughout the year. This will give you an opportunity to watch birds at close range in all seasons. How many kinds of birds are there? There are more than 9000 known species of birds in the world. About 578 species have been found in Canada and its coastal waters. What do you know about birds? Did you know? A tiny bird like the Ruby-throated Hummingbird has some 940 feathers, while a large bird like the Tundra Swan has at least 25,200. The largest native bird of North America is the Trumpeter Swan. It weighs on average about 11 kg and has a wingspread ranging from 2.5 m to 3 m. The number of feathers can vary seasonally, and birds living in cold climates may have more feathers in winter than in summer. Flight feathers Flight feathers are one of the most important parts of the bird s flying machinery. Primaries (long outer-wing feathers) are the strongest feathers in a bird's plumage and are shaped to provide the support for flight. They also help a bird control its movements and speed by rotating in flight. Secondaries (inner-wing feathers) are generally shorter than the primaries. They smooth the flow of air over the bird's wing. Coverts are smaller feathers that overlap the bases of the primaries and secondaries. They also help smooth the flow of air. Page 3 of 11

4 Tail feathers Birds use their tails for steering, balancing, braking and display. Tail feathers come in many shapes, sizes and colours. Contour feathers All body feathers are contour feathers. They protect and insulate the body and give a bird its shape. They protect birds from cold and help keep them cool on warm days. Down feathers Down feathers are hidden under the contour feathers next to the skin. Their barbs do not lock together but spread out to form a soft irregular mass. Down is one of the most effective known insulating materials. Where do feathers grow? We have clipped the leathers on one side of this mounted American Crow so you can see that feathers do not grow everywhere. Instead they grow on specific areas of the body called the feather tracts. Sections of the wing and tail feathers have been stripped to show that they are anchored firmly to bones. Feather structure Only under high magnification can we see the intricate network that makes up a feather. A typical feather contains a shaft, vanes, barbs, barbules and hooks. These complex structures interlock to form an extremely strong, but light surface. A single feather may have up to a million individual parts. A feather of the Lesser Golden-Plover magnified 500 x. The shapes of the barbs, barbules and hooks are shown clearly. The tiny hooks hold the overlapping barbules together to form the flat vane surface. Take a closer look Did you know? The long-distance flying champion is the Arctic Tern. Its annual round-trip migration from the Arctic to the Antarctic probably exceeds the circumference of the earth. Hummingbirds, the tiniest birds, have wing beats so fast that they appear as hazy as an airplane propeller in motion. Their wings may beat up to 50 to 75 times a second. Page 4 of 11

5 The smoothly streamlined Peregrine Falcon is said to dive on its prey at speeds up to 325 km an hour. Powerful wings A bird's wing is light, strong and flexible. It is slightly curved to pull the bird upward as it flaps through the air. The size and shape of wings vary according to a bird's lifestyle, but wings all share the same general pattern. Fast takeoff Birds that fly less frequently than others, such as pheasants and grouse, have short, broad, rounded wings. This wing design provides them with quick and powerful lift but is less efficient for sustained power. Speed and endurance Some of the fastest fliers - falcons and swallows - have long, pointed wings. This streamlined profile creates the least resistance as the bird moves through the air. Soaring and gliding Long, narrow wings, like those of albatrosses and gulls, and wide, expansive wings, like those of hawks, are both well suited for soaring and gliding. Flight muscles Large breast muscles are needed to propel a bird's wings. The size of these muscles is closely related to the habits of the bird. In strong fliers, such as swallows, breast muscles can account for as much as 25 to 35 per cent of the total body weight. For ground-dwellers that prefer to run instead of fly, such as rails, the leg muscles may be as large as the wing muscles. A streamlined body Although they differ in size, flying birds have a similar overall shape: broad in front and tapering to a slender tail in the rear. This streamlining of the body lets them pass through the air with little friction and much stability. Saving Weight Bone is generally heavy and birds have to work within strict weight limits to fly efficiently. Mammal bones are dense, but the long bones of flying birds are hollow and reinforced with lightweight internal struts. Page 5 of 11

6 Can you identify these birds? Using the field guides and information below, try and find out the names of these birds. The identities of the mystery birds can be found at the end of the Birdquiz. It is a warm summer day. You are standing at the edge of a mixed forest and you hear a highpitched song coming from one of the spruce trees. Walking over, you catch a glimpse of some birds, like the ones on display, flitting among the trees. What kind of song is it singing? Bird songs are quite distinctive and are valuable aids in locating and identifying birds. Begin your study at home by listening to tape recordings. Learn the songs of a few common species first. As you gain experience, you will be able to identity many birds by their song alone. What shape is it? The shape, or silhouette, of the bird is one of the most important clues to its identification. To an experienced eye, the silhouette of a bird is often enough to identify it. Differences in shape can be effective in telling similar species apart. What size is it? Try to determine the size of the bird you are watching by comparing it with the size of a bird you know. Is it smaller than an American Robin, larger than an American Crow? What colour is it? Colour is the one thing that many people think of first. Yet as an identification aid, it may not be the most reliable. Plumages may change with the seasons, between males and females, and with age. Does it have any distinctive markings? Fieldmarks (distinctive markings) are good clues to identifying birds. These distinctive markings can be wing bars or wing patterns, eye stripes, crests, crown markings or colour markings. What is it doing? Watching a bird's activity can provide important clues to its identification. For example, woodpeckers and nuthatches might be confusing to a beginning birdwatcher. Both are often observed going up and down a tree. But a simple difference separates the two groups. Woodpeckers back down the trunk of a tree tail first, while nuthatches turn and go down headfirst. Page 6 of 11

7 Where did you see it? Each species occupies a specific habitat. Knowing what species you are most likely to see in a particular region will make identification easier. Once you know a bird s habitat, check a range map to see if it is apt to occur in the area you are birdwatching. This knowledge of a species habitat and range may help you to separate one species from other seemingly similar species. Attracting birds in summer Building and setting out nest boxes is an effective way to attract birds to your lawn or garden. As wild habitats disappear, carefully placed nest boxes provide valuable nesting sites for many cavity breeding birds. Attracting birds in winter By setting out bird feeders in late fall and keeping them well stocked until spring, you can attract a variety of birds to your backyard throughout the winter. Although birds that stay in Canada all year are adapted to surviving the winter, bird feeders can help to supplement their natural diet. Setting up a feeding programme will also give you an opportunity to watch birds and observe their behaviour at close range. Window Shelf Feeder Window shelf feeders are perfect if you want to watch birds from the comfort of your home. But encouraging birds to come that close to your house may be difficult. Try installing a window shelf feeder after birds have become accustomed to using other feeders in your yard. Hopper-type Feeder Hopper-type feeders automatically regulate the amount of seed that is available at any one time. This style of feeder is ideal for distributing seeds in bulk, and is convenient for people who may be away for a few days at a time during the winter season. Suet Feeder Suet feeders are useful in preventing larger birds from carrying away entire pieces of suet at one time. Page 7 of 11

8 Ground Table Feeder A ground table feeder will attract both ground-foraging and perching birds. Ground feeders should be set up in an open part of your yard, away from shrubs, to reduce the threat of cats and other predators. Sunflower Seeds Sunflower seeds are highly nutritious and a favourite food of most winter birds. They are enjoyed by woodpeckers, jays, finches, nuthatches, chickadees and juncos. Suet Suet (white beef fat) is a good source of energy which when converted into body heat will keep birds alive on the coldest nights of the year. It is a popular food of insect-eating birds such as chickadees, woodpeckers and nuthatches. To make a gourmet bird food, combine suet with peanut butter and a variety of nuts and seeds. Mixed Seed A mix of corn, cracked grains, rolled oats and peanuts will appeal to most winter birds. Small quantities of fine sand can be added to this mixture to help the birds digest their food. Tree Swallow Nest Box Tree swallows are gregarious and will nest in boxes placed as close together as 3 metres. The nest boxes should be placed in an open area, and if possible within sight of water. Bluebird Nest Box Bluebirds may attempt to nest twice in one year and for that reason you may wish to build two boxes for each pair. This will allow the female to lay her second set of eggs in a clean box, free of parasites. Parasites are common in young birds and increase rapidly as the season progresses. The young usually leave the nest before they become a major problem. However, if the adults attempt to raise a second brood in the same box, already heavily infested with parasites, the young rarely survive. Purple Martin House Purple Martins nest in colonies and once established, will return year after year to the same location. Their multiple-unit houses should be set in open areas, free of obstacles, to allow the adults to swoop onto nest sites. Page 8 of 11

9 Hummingbird Feeder Hummingbirds are attracted to feeders filled with concentrated sugar water. There is no need to include artificial colouring in the solution. Although hummingbirds appear to favour red, they are indifferent to colour once they have found a good source of food. Backyard Baths Backyard baths are used by birds year round for both drinking and bathing. They can be as simple as a shallow basin set on the ground, or as elaborate as a hollow in the ground lined with rocks and cement, made to ressemble a natural pool. Birds are attracted to the sound of moving water. By installing a hose that allows a trickle of water to flow into the bath, you will attract many birds that otherwise might not find their way. Bird Quiz What do you know about birds? Test yourself by trying this quiz either before or after you visit the exhibition. The answers to these questions can be found at the bottom of the page. Good Luck! 1. About how many living bird species are there? a) 1000 b) 9000 c) 20, What is the largest living bird? a) Emperor Penquin b) Emu c) Ostrich 3. What is the smallest living bird? a) Bee Hummingbird b) Black-capped Chickadee c) Rubycrowned Kinglet 4. What did feathers evolve from? a) fur b) nerve endings c) scales, similar to those found on reptiles today 5. What single characteristic identifies birds? a) feathers b) ability to fly c) bills Page 9 of 11

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11 6. What special adaptations have birds developed for flight? a) light feathers b) thin hollow bones c) powerful wings d) all of the above 7. What is the easiest way to identify birds in a dense forest? a) by their colour b) by their songs c) by their habitat 8. Where are you most likely to see a Steller's Jay? a) a coniferous forest in B. C. b) a woodland in P. E. I. c) a Manitoba farm field Answers 1b, 2c, 3a, 4e, 5a, 6d, 7b, 8a The identities of the mystery birds in the Exhibition Module How to Identify Birds are the Rubycrowned Kinglet and Golden-crowned Kinglet. Page 11 of 11