AAB-02: Nests and Eggs Overview: Students learn about the wide variety of nests and eggs and their purpose in a bird s life.

Transcription

1 An activity from the Environmental Volunteers AAB-02: Nests and Eggs Overview: Students learn about the wide variety of nests and eggs and their purpose in a bird s life. Program Area: All About Birds Grade Levels: K-2 EV Learning Objectives: 1. Birds build a variety of nests to lay their eggs. They do not live in their nests. 2. Nests can be made out of many things including sticks, leaves, mud, feathers, spider s webs, and even trash. 3. Baby birds hatch out of eggs. The eggs have many useful shapes and colors. EV Sustainability Principles: E. Understanding the beauty of our planet, the elegance of natural systems, and the interconnectedness of all its parts. MATERIALS LIST Nests: a. House finch b. Hummingbird c. American Robin d. Goldfinch e. Bushtit f. House Sparrow (Peninsula) g. Towhee (South Bay) Eggs: a. Chicken b. Ostrich c. Robin (replica-plus a real one in South Bay) d. Hummingbird (replica) e. House Finch (replica) f. Red-tailed Hawk (replica) g. Killdeer (replica) h. Crow (replica) Skins: a. American Robin b. Anna s Hummingbird c. House Finch Killdeer nest photo Bird development visuals CALIFORNIA EDUCATIONAL STANDARDS All standards are for science unless otherwise noted. 1 Kindergarten 2a. Students know how to observe and describe similarities and differences in the appearance and behavior of plants and animals (e.g., seed-bearing plants, birds, fish, insects). 4b. Describe the properties of common objects. 1 Note about EEI Learning Objectives: this learning station supports these objectives of the Education and the Environment Initiative s Environmental Principles and Concepts. As the learning objectives do not have their own numbering convention, the one used here show the number of the standard before the dash and the number after the dash is the bullet point from the list of objectives for that standard. AAB-02: Nests and Eggs Page 1 Last Updated 3/13/16

2 First Grade 2c. Students know animals eat plants or other animals for food and may also use plants or even other animals for shelter and nesting. EEI Learning Objectives 2c-3 List examples of the materials that animals use to make shelter and nests and categorize the sources of those materials as plants or animals. Second Grade 2b. Students know the sequential stages of life cycles are different for different animals, such as butterflies, frogs, and mice. EEI Learning Objectives 2b-1 Identify reproductive cycles for different animals such as butterflies, frogs, and mice. ACTIVITY INTRODUCTION (Time required: 2-3 minutes) ASK: Today we are going to talk about nests and eggs. Why do birds build nests? RESPONSE: They build them to have a place to lay their eggs and to raise their young. It is important to remember that nests are not the bird s house. ASK: If birds don t live in a nest, where do they live? Where do they go when it s raining? RESPONSE: Birds will seek shelter in trees or under bushes. They might even hide in the eaves of your house, or under a deck. They will find shelter wherever they can. ACTIVITY 1: Garbage Nest DO: Pull out the garbage nest (aka House Sparrow or Mourning Dove nest). Pass it around the group. ASK: Look very closely at this nest. I want each of you to tell me one thing you see that this bird used to build the nest. RESPONSE: Students will tell you what they see. If you have a smaller group, you might consider passing it around a second time so the students can find even more things. EXPLAIN: Birds will make their nests out of pretty much anything. Some make theirs out of things like we found in this nest. Some also will use mud, or spider s webs, or a hollow in a tree, or even someone else s nest. We can tell from the things the nest is made out of who is likely to have made it. ACTIVITY 2 Nest and Egg Matching EXPLAIN: I have three different nests here. Let s take a look at each of them. DO: Have the students tell you 2-3 things they notice about the nests. ASK: A few guiding questions about what they might know about the bird that built the nest, such as how big was the bird that built it. RESPONSE: Students will give their responses based on your nests. EXPLAIN: I have three different eggs here. Let s take a look at each of them. DO: Have the students tell you 2-3 things they notice about the eggs. AAB-02: Nests and Eggs Page 2 Last Updated 3/13/16

3 ASK: A few guiding questions about what they might know about the bird that laid the egg, such as how big was the bird that laid it. RESPONSE: Students will give their responses based on your eggs. ASK: Which egg do you think goes with which nest? RESPONSE: Students will likely figure it out. If they don t, let it be for now. When they look at the bird skins and match those encourage them to correct their answer if they think they need to. Ideally, students will come up with the correct answer on their own. EXPLAIN: I have three different bird skins here. Let s take a look at each of them. DO: Have the students tell you 2-3 things they notice about the birds. ASK: Can you match the bird with the nest and egg that they go with. Make a correction to your guesses about the eggs if you think you need to. RESPONSE: Students will give their responses. If they don t have it correct, ask a question that may guide them to the correct answer, such as Do you think that great big bird would be comfortable in that little nest? ACTIVITY 3: Eggs EXPLAIN: The three eggs we have looked at are all a little different. But some bird eggs can be extremely different. Take a look at these! DO: Bring out the Killdeer, Scrub Jay, and Crow eggs ASK: Tell me some things that are different about these eggs. RESPONSE: Students will note the colors, the spots, the sizes, etc. ASK: Why would bird have such different eggs? RESPONSE: Students give their answers. Egg size is almost always related to the size of the bird. ASK: What would colors like the killdeer egg be useful for? RESPONSE: Camouflage. These eggs are hard to see in a killdeer nest. DO: Show a picture of the killdeer nest. EXPLAIN: Birds can also use the color and markings to identify their own eggs. This helps the bird know if another bird has laid eggs in their nest. ASK: Why are eggs shaped as they are? RESPONSE: The eggs are all rounded to make it more comfortable for the birds to lay and then to sit on to incubate. ASK: So why do some eggs have one end that is extra pointy? RESPONSE: Students will make their guesses. DO: Roll the killdeer egg on the table. ASK: What happened? RESPONSE: The egg rolled in a circle. EXPLAIN: Some birds don t build great nests, so the pointy shape helps keep the egg from rolling away. It also helps the eggs fit in the nest better as the pointy ends all go towards the center of the nest. ACTIVITY 4: Bird Development DO: Using the Bird Development visuals, go through the steps of chick development. These steps are basically the same for all birds that are born helpless. Some birds, such as ducks are born already able to walk around and feed themselves. Bird AAB-02: Nests and Eggs Page 3 Last Updated 3/13/16

4 incubation periods range from roughly a week and a half to two months. The chicks can stay in the nest for a few days to several months. ASK: How does the chick get out of the egg? RESPONSE: They peck their way out with the egg tooth, or the sharp tip on their beak that will fall off a few weeks after hatching. ASK: What kinds of changes do you see in the baby birds as they develop RESPONSE: Students will give their various observations. EXPLAIN: When the chicks leave the nest it is called fledging. A fledgling bird is like a teenage bird. They are learning to fly and are often just found on the ground. They should be left alone, as their parents are usually nearby. If they are somewhere dangerous, ask a parent to help you shoo them into a bush. ACTIVITY 5: Unusual Nests and Eggs You can fill the rest of your time by exploring some unusual nests and eggs of different birds. The bushtit nest is a great example of the amazing nests birds build. They weave this intricate nest at the end of a long branch where predators like cats can t get to it. The bushtit is a tiny little bird similar in size to a humming bird. Of course, the big wow for the students is the Ostrich Egg. Students are allowed to handle the egg, but be careful no one drops it. TWO-MINUTE WARNING (Time required: 2 minutes) Review the key concepts of the kit. ALTERNATE SCRIPTS HELPFUL HINTS You will likely not be able to get to all of the activities described. The Garbage Nest activity (#1) is important for the Kindergarten and First Grade standards and can be dropped for second grade. The Egg Development activity (#4) is important for the Second Grade standards and can be dropped for Kindergarten and First Grade. GLOSSARY Incubation-the process of keeping an egg warm to help the development of the embryo. Clutch-the number of eggs laid and incubated together. Embryo-the developing baby bird inside of an egg. Egg tooth-a hard sharp point on a baby bird s bill to assist with hatching. AAB-02: Nests and Eggs Page 4 Last Updated 3/13/16

5 SCIENCE BACKROUND AMERICAN ROBIN Turdus migratorius Description: A medium-sized songbird. Sexes similar, but females slightly smaller, duller. Bill yellow; upperparts grayish-brown, with darker head and tail; underparts brick red with white throat, white lower belly; eye dark with broken white eye-ring; white spots on corners of tail. Length average 25 cm (10 in) Weight 77 gm (2.7 oz) Distribution: Migratory. Nests continent-wide from the Arctic Ocean in Canada and Alaska, south to the edge of the deserts from Texas to California. Winters from the Canadian border south into Mexico. Habitats: Common. Generalist - inhabits forests, woodlands, gardens, parks. Habits: Territorial in summer, gregarious in flocks in winter. Successful around humans. Very adaptable in many habitats. Most populations are migratory, and winter numbers may vary greatly. Food: Omnivorous. Diet about 60 percent vegetable, 40 percent animal. Eats fruits and berries, earthworms, insects and other invertebrates, eggs. Expert at catching worms in a lawn. Reproduction: Male song establishes a nesting territory. Female builds a mud cup nest, usually lined with fine grass, on a tree branch, window ledge, the ground or in brush. Both parents incubate ~14 days. Both parents feed nestlings. Fledge in about18 days. Parents tend fledglings about 2 weeks. The male often tends the first brood while the female renests. One or two broods. Cool facts: - American Robins are the largest and most widespread North American Thrush. - In their zeal to repel intruders, Robins will often attack their reflections in a window or mirror, sometimes even damaging the reflecting surface. Description: A medium-sized, stocky hummingbird. Males larger, more colorful. Both: Bill medium length, straight, black; cap, nape and back irridescent green; wings dark gray; belly ashy white; eyes dark; legs and feet small, black. Male: Forehead and throat brilliant rose red; tail all dark gray. Female: Forehead green; throat white with a few red or purplish spots; outer tail feathers white- tipped. Juvenile male: like female, but without white in tail and usually with more throat color. Length average 10 cm (4 in) Weight 4.3 gm (0.15 oz) DIVERSITY AMONG BIRD EGGS by Bobbie Callison As one examines a variety of bird eggs within various species, it becomes obvious that there is a great diversity among color and shape. Egg color is under genetic control but there appears to be considerable. Birds that build nests in tree holes have different colored eggs from those birds that build nests on the ground A shape of eggs from round to oval to pointed varies. The next question to ask is, why? AAB-02: Nests and Eggs Page 5 Last Updated 3/13/16

6 Egg color is determined by pigments secreted from special cells lining the oviduct. As the egg passes through the oviduct, pressure causes the release of these pigments on to the eggshell. Motion of the egg as it passes through oviduct affects color patterns. If the egg stops moving momentarily, spots will appear. If there is continuous LO movement, brush stokes of color appear. If no special cells are present, white eggs appear. Many ground nesting birds such as killdeer have colored eggs for camouflage. But, what about the exceptions for example? It is suspected that since these birds hide their nests in dense vegetation, and the female well camouflaged, egg color is not necessary. Pigeons and doves lay uncamouflaged eggs. But these birds incubate the eggs immediately so that they are never left uncovered no need for the extra of providing organs for color. Hole nesting birds (woodpeckers) that excavate their own nests lay white eggs as there is no need for well protected eggs to be colored. But how do we explain hole nesters that lay spotted eggs (nuthatches). These do not excavate their own nests but remodel existing holes. They were probably previous open nesters who switched to hole nesting and the spotted equipment stayed with the bird. The shape of the egg is genetically determined by the environment in which the nest is built. Ground nest as the killdeer and sandpiper lay four eggs with pointed ends toward the center. In this manner, all eggs are incubated easily by the brooding female. On the other hand, cliff nesting birds such a murre or tern have another concern to keep eggs from rolling off a ledge into the sea. These birds lay elongate eggs that spin in a small circle when bumped rather than rolling. When egg rolling is not a concern round eggs may be laid to provide maximum security for the developing chick (owls, eagles). EV Suggests- Tips, Tricks, and News REFERENCES Field Guide to Western Birds Nests, by Hal Harrison Nests, Eggs and Nestlings, by Colin Harrison Urban Roosts, by Barbara Bash AAB-02: Nests and Eggs Page 6 Last Updated 3/13/16