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Monday, March 16, 2009

More Owl Pellet Analysis

Last week I visited the Lynnwood Elementary School and worked with 4th grades doing Owl Ecology and Owl Pellet Dissection. Here are the results:

Mrs. Janssen’s class – 24 rodents, 1 shrew, 0 moles, 0 birds in 11 pellets
Mr. Miller’s class – 14 rodents, 1 shrew, 0 moles, 1 bird in 6 pellets
Ms. Shields’ class – 26 rodents, 0 shrews, 0 moles, 0 birds in 11 pellets
Mrs. Lodge’s class – 23 rodents, 0 shrews, 0 moles, 1 bird in 11 pellets

For a total of 87 rodents, 2 shrews, 0 moles, 2 birds in 39 pellets.

Definitely rodents are the most eaten food. In my hypothesis that I discuss with the students I state that shrews are the second most eaten food. Our analysis seems to indicate that shrews and birds are tied for second.

If we look at more owl pellets (see Previous Posts - More Owl Pellet Data and Owl Pellets and Predator Prey Relationships) we see that, indeed, shrews are the second favorite, with moles and birds a close tie for third favorite.

If we look at the number of animals eaten per pellet we find 91 animals eaten in 39 pellets for an average of 2.3, very close to the 2.5 that I predict. This supports the thought that a barn owl eats between 2 or 3 animals before it gets full and proceeds to digest their food producing a pellet.

Thursday, March 05, 2009

Chicken Egg Incubation



Hello scientists! It's that time of year to be ornithologists studying the life cycle of birds by incubating chicken eggs. I have incubators going at the Sapphire Elementary School and the Smith Clove Elementary School, both in Monroe-Woodbury, and will be starting incubators at the Martin Luther King Magnet School in Schenectady.




I start of the incubation program introducing students to the ecology of the chicken, a bird that has been living with people for many thousands of years. Of course, people have wanted chickens living with them for all this time because of the food they provide - their eggs and the chickens themselves - chicken nuggets, barbequed chicken, roast chicken or chicken soup with rice - "happy once, happy twice, happy chicken soup with rice". Happy for us because of the food they give us. I'm not sure how happy for the chicken since, if we are going to eat it, it has to be killed and then cut up in preparation for it to be cooked for our food.




The word chicken doesn't tell us whether it is a male or female. Like bluebird, mallard or bald eagle, it's the name of the kind of bird it is. When I say chicken, I am talking about the group, as a whole. I like to talk to students about what chickens, as a whole need to do to survive. I call it chicken business - find food, find water, look out for danger and go to the bathroom (the top four). Other chicken business includes, talking to other chickens, resting, exercising, taking a bath (not a water bath, but a dust bath to get rid of biting insects). All the activities that both male and female chickens do every day.




The male chicken is called a rooster. A farmer doesn't need a rooster to get eggs, all the farmer needs are the female chickens, the hens. A farmer also doesn't need a rooster to wake them up in the morning either - you see the roosters crow (that's what their "cockle-doodle-do" call is called) at all hours of the day and even night. That crowing is important for why the farmer might have a rooster. When roosters crow they are saying, "Check me out I'm so good looking!" This message is for the hens. If they can get the attention of the hens then they might mate and a baby chick could be in the egg laid by the hen.




The hens lay the eggs, take care of the eggs and take care of the baby chicks. Roosters pretty much do nothing to help her out in these matters. Most of the time the hens lay the eggs in the chicken coop or hen house as it is sometimes called. They usually don't make much noise, they go in lay an egg, it doesn't take much time, and when they're done it's off to do chicken business. The farmer comes and takes the eggs out of the coop and the chickens keep laying more eggs. A hen in one year can lay about 200 eggs (one egg every other day on average), although the world record egg layer laid a little more than 370 eggs in one year. That meant she laid an egg a day, with a few days in which she laid two eggs.




A hen that wants to have a family, though, will not go into the coop to lay her eggs. She'll try to find a secret hiding place instead. This hen would be called broody. She'll return to her secret hiding place each day that she is ready to lay an egg until 5 or 6 eggs are there, and she stops laying eggs. This would be called a clutch of eggs. She will now use her body to keep the eggs warm, at the special temperature of 99.5 degrees. At that temperature the embryo begins to grow. The hen will incubate the eggs for 21 days, hardly ever leaving to do chicken business. Every now and then the hen moves the eggs around, ensuring the embryo is doesn't get stuck in one spot in the egg.




When the chicks hatch mother hen's incubation business is done and new business is at hand - taking care of baby chicks and teaching them chicken business - like where to get food and water and most importantly how to look out for danger (no mother hen doesn't need to teach the chicks how to go to the bathroom - they already know how to do that). This business will take many weeks and in all this time the hen will not lay any eggs. If a farmer let's all the hens go broody there won't be any eggs to collect. Farmers usually don't let the hens incubate the eggs. The farmer looks for all the secret hiding places.




If a farmer needs new chicks the farmer has to incubate the eggs, using an incubator. The incubator keeps the eggs warm, at 99.5 degrees. Water is placed in the incubator to provide moisture for the growing chick. The eggs are turn frequently, just like mother hen would. With good care and luck, baby chicks hatch in 21 days.




One of my favorite activities is to candle the eggs at about the 8th or 9th day of incubation. A light is shown through the egg, casting shadows on the egg shell of four different things that tell of the growing chick; an air space, veins, eye spot and movement of the eye spot and veins. View this video of an egg I candled at Sapphire Elementary - it's a work in progress. I'm having some difficulties with the technology of the webcam but will work on it and hopefully get a better video soon.