A Little Bit More
As the poster points out, it should be no surprise to anyone to be reminded that our actions affect the environment, often in ways we can’t predict. Who would have thought that acid rain would have this effect on songbirds? Makes one think about Rachel Carson’s book, “Silent Spring” when you learn about this problem!
Acid rain occurs when moisture in the atmosphere combines mostly with
oxides of sulfur and nitrogen from coal, oil, gasoline and other hydrocarbon uses. Probably the most widely recognized result of acid rain has been the acidification of lakes in northeastern U.S. and Canada that are downwind of industrial centers. The Adirondacks alone, a huge state park in New York State, has lost many of its lakes (some lakes can no longer support life) due to an increase in acid levels of the water.
The Cornell Laboratory of Ornithology pulled lots of data together to get a look at Wood Thrush populations in North America. Wood Thrush populations between 1966 and 1999 were found to have declined 56% over this period across their breeding range causing alarm among researchers. Although scientists could document the decline in population, they didn’t know what was causing it.
After looking at a variety of possibilities, scientists were able to determine that areas of high acid rain AND significant decreases in breeding success of Wood Thrushes were linked. Of course, knowing what the problem is, is only the first step – now researchers are trying to determine how to reverse this trend. One especially interesting feature in this project has been the input from lay volunteers. Interested citizens, from all walks of life, were instrumental in providing much of the data the Ornithology Lab used to better understand population dynamics of Wood Thrushes.
Activities
Calcium Provider
Objectives: Empower people to make changes, even if small
Materials: Eggshells
This is a simple, easy-to-do activity, yet one that can make a difference for both the birds and the participants.
1. Have your students bring in eggshells from home. It’s best if the shells are completely dry before they get stored anywhere so you may want to ask students to dry them at home before bringing to class (they can be left out on the counter overnight). As the eggshells arrive, they should be stored in a container that breathes (avoid plastic) so any residual moisture will dissipate.
2. Once you’ve accumulated “enough” eggshells (you be the judge of how many you want to deal with) they need to be crushed prior to being distributed to the birds. Don’t worry too much about the size of the pieces as long as you have a variety for birds to choose from (small birds will choose smaller sizes, etc).
3. The best time of the year to offer your shells is in the early spring when birds are beginning to build their nests and lay their eggs, but they often take them at other seasons in smaller quantities. Simply scatter the shells around your feeding areas. If you aren’t feeding the birds, you can still scatter shells in any areas you think birds will frequent.
4. If you can keep a general idea of how many shell fragments are lying around, you can approximate how attractive they are for the birds. As the females approach egg-laying, they’ll be more and more interested in these shells and will add them to their diet. Males too need calcium and may or may not take shells as their own calcium needs dictate. Keep in mind that in some areas, calcium will be easier to acquire so your shells will be more or less attractive to the birds based on this factor.
Key Concepts
Environmental Issues, Populations and Ecosystems, Reproduction
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.
Posted by Laura Brown on May 25, 2006 at 04:24 PM
Q: Hello,
I was wondering if you could tell me which animals have tapetum lucidum? I know that nocturnal hunters have them, and also someone said underwater mammals have them but I'm not so sure. Thanks and I look forward to hearing from you!
A: I found a brief discussion online of the different kinds of tapetum lucidums with a list of animals that I'll share for you. It's a bit formal so I'll add a few comments to make it more user-friendly.
"Some species (primates, squirrels, birds, red kangaroo and pig) do not have this structure and they usually are diurnal animals. In vertebrates, the tapetum
lucidum exhibits diverse structure, organization and composition. Therefore, the retinal tapetum (teleosts (bony fishes), crocodilians, marsupials (pouched mammals), fruit bat), the choroidal guanine tapetum (elasmobranchs (sharks), the choroidal tapetum cellulosum (carnivores, rodents, cetacea (whales and porpoises), and the choroidal tapetum fibrosum (cow, sheep, goat, horse) are described."
So it does look like at least some of the underwater mammals do indeed have a tapetum lucidum. I'm quite sure there are other mammals not included in this piece but you can probably figure that those living in a rather dark environment, whether water or nocturnal, are most likely to have this adaptation. Hope this helps.
Posted by craig citizen on January 18, 2006 at 04:48 PM
Q: i would like to know what the word for "animal eye shine" or "eye glow is". i knew the word as a child but have now forgotten it. i am not referring to the part of the animal's eye that reflects the light but the term for that phenomena. a friend of mine says there is not such a word, but i disagree. we wagered a car wash on this. please help!
love, craig
A: Gosh Craig, I hope I can help you on this so you don't have to provide a car wash! But the only term I know for this phenomenon, is called "eyeshine". Your friend is wrong if he says there is no term, it is eyeshine as I've mentioned. Sure hope this helps and you get a clean car out of this. Thanks for asking.
Posted by margaret o'leary on March 21, 2005 at 08:59 PM
Q: What are some nocturmnal animals you might see out in the woods and waters in the Adirondack mountains in the spring, summer, and fall?
A: Those that come to mind include the Bobcat, Coyote, Flying Squirrel, Great Horned Owl, Long-eared Owl, Barred Owl, Screech Owl, Whip-poor-will, White-tailed Deer, Cottontail Rabbit, Mink, and Beaver. There are going to be lots of insects, spiders, and other "creepy-crawlies" active at night too.
Posted by leah on March 08, 2004 at 04:45 PM
Q: hey there, just wondering what makes certain minerals glow specific colors under blacklight. (i.e. why does amber glow orange and not blue, & why do some minerals like fluorite glow either white, yellow, or blue depending on the stone?)
and why do some animal eyes reflect yellow, for example, while others reflect green?
i've been having trouble finding information on these things, so any information you can find on these topics would be greatly appreciated! thanks!
A: I really can't answer your question on minerals as that's out of my area of expertise. I can, however, give you some info on the eye reflection.
Eyeshine, the reflection of colored light from an animal's eye, is due to a reflective layer in the back of the eye called the tapetum lucidum (ta-PEE-tum LOO-sih-dum). This layer, which literally means "bright carpet", is found in most nocturnal animals or animals in living in dim environments (like underwater). In many of the hoofed-mammals, the tapetum lucidum is composed of glistening connective tissue fibers while in many carnivores and sharks, it is composed of fiber-like crystals of guanine. As light passes through the eye, various layers in the eye filter the light, causing different colors to be reflected as eyeshine in different kinds of animals. The eyeshine of a bear may be a deep red, a deer's glows with an orange-yellow light, while a cat's may show a greenish tint.
Posted by sarah on December 08, 2003 at 03:27 PM
Q: Are there any safety concerns when dissecting owl pellets found in the outdoors? Are there any precautions that should be taken when handling and dissecting them?
thanks
A: Good question and I understand why you've asked. But, I really don't think there is any cause for concern. I have done this with 4th and 5th graders and took the sensible precaution of having students wash their hands after dissecting the pellet and made sure no one put their fingers in mouth or eyes while working, but that's just stantard practice anyway. If you wish, you could have students dissect their pellet with a couple of sharp sticks and then there'd be no need for handling. Keep in mind that the pellet has gone through the digestive process in the stomach of a bird and has dried out quite a bit so most organisms are no longer active/alive. Furthermore, these organisms, if still active, are bird-related, not mammal-related in large part. We certainly get "germs" from all kinds of sources but keep in mind that almost all are not a danger to humans.