- Identify these 6 common species seen during this year’s
Great Backyard Bird Count. (6 pts)
A. This bird is about 6" long and hangs around in flocks. Seen on campus occasionally
B. This small bird (4") is seen in gardens, fields, and forest edges.
C. This 10" bird is found all over town.
Cedar Waxwing
American Goldfinch
American Robin
D. This 10" bird is all over campus.
E. This little guy (4") is found in forests and on bird feeders.
F. Male on the left, female right (5"). Seen all over Charlotte.
Northern Mockingbird. Turns out this wasn’t on the list, so I gave everyone a pass on this, unless you called it a Canada Goose.
Carolina Chickadee
House Finch
- Definitions (3 pts each/30 total):
- Metapopulation- A group of subpopulations of a species that are interconnected genetically through immigration and emmigration.
- Biodiversity-The number of species, their relative abundances, and the genetic diversity in an ecosystem.
- Population bottleneck-When a population suffers a relatively sudden and drastic reduction in numbers. Usually results in a significant loss of genetic diversity.
- Biomagnification-The accumulation of a toxin as it moves up the food chain.
- Xenobiotics-Man-made chemicals that are biologically active (not toxins or pesticides) when they get into other animals. They usually have some effect during embryological development and often affect reproduction.
- Muscle insertion-where a muscle attaches to the thing it is going to move when it contracts.
- Pre-basic molt – The molt that brings the basic (non-breeding season) plumage. Includes all feathers.
- Emlen Funnel – a cone-like device (not an experiment) with an ink pad at its base used in experiments on migration.
- Habitat island – a patch of some habitat surrounded by some different, often man-altered, environment.
- Ecosystem services – Things that ecosystems do for us (not the other way around, as many answered), like filtering water before it goes into rivers and streams, pollination of farm crops by insects living in the habitat around our farms. Saltwater marshes are nursery grounds for many ocean-going fish that we harvest. The Mississippi delta protects New Orleans (more or less!) from hurricanes.
- What advantage does egg laying confer on birds? (4 pts) – Weight reduction and the eggs probably couldn’t develop at the high temps in the female’s body.
- How are reptile eggs different from bird eggs? (2 pts) Reptile eggs are leathery and can actually absorb water. They are not laid in the water, as some answered—that’s what amphibians (frogs and salamanders, etc) do.
- Roughly how long would it take a female Mallard to lay a clutch of 12 eggs? 2 pts – a day to a day and a half or so for each egg, so anywhere from 12-20 days, roughly.
- Why does the female Mallard want all the eggs to hatch on the same day? 2 pts – They are precocial, so they all have to leave the nest at the same time. She has to lead them to water. She can't do that while still incubating eggs.
- How does the female make this happen? 2 pts – incubates only after the last egg is laid.
- Brood parasites and their hosts are said to engage in an "evolutionary arms race" Explain what this means. (4 pts) – host bird species evolve ways to avoid having some other species lay eggs in their nests, while the brood parasites evolve ways to get around the defenses of the host species.
- To use the sun’s position for orientation, once it sees the sun, what does a bird need to know? (3 pts) – the time of day. Not what direction they need to go. They know that instinctively, but they can only use the position of the sun if they know the time of day.
- (2 pts) (2 pts) Some species of waterfowl (Anseriformes) have a molt migration and head north prior to their southerly migration in the fall. Why go north to molt? Cite two reasons. – longer day length means more time to forage, also less competition (maybe). They don’t do it to avoid predation.
- (9 pts) True or false: (All of these were repeats, so no
excuse for missing them!)
__F_About 70% of bird species are known to migrate.
__F_Birds store energy for migration as fat in adipose tissue deep in the body to keep their center of gravity low. 59
__F_The ultimate cause of migration is a change in day length, the proximate cause relates to changing resource availability.
__t_The best time to see spring migrants is right after a high-pressure system has passed through.
__T_ The photorefractory period prevents birds from getting into reproductive condition in the fall.
__F_ Because of the importance of flight feathers, all bird species molt all their retrices and remiges annually.
__F_ Because they provide most of the food for the growing young, females will often delay their molt.
__T_ Sex hormones restrict the production of thyroid hormones, which are important in initiating molt. This has the important effect of limiting the overlap of molt and reproduction.
__F_ Airsacs are another of the many adaptations birds have evolved to reduce their weight.
- (3 pts) Why should you spend a bit more money at Starbucks and ask the barista for "shade-grown coffee" - shade-grown coffee plantations provide habitat for local and migrant bird species.
- (4 pts) What are keystone species. Explain using an example. – a species on which many others depend. Example we used several times in class were primary cavity nesters, which excavate nest cavities that many other species, which need cavities but can’t excavate them themselves, require. Lose the primary cavity nesters and you lose a lot of other species.
- (4 pts) Give four characteristics of birds that make them such good study subjects for so many fields of biology? Size, same wavelenghts as us, diurnal, taxonomy well known, reasonable number of species, widespread, etc.
- What happens to Basal Metabolic Rate when a female is laying eggs? (Careful! This is pretty tricky—I even led you astray on it in a response to an email question because I gave the obvious answer without thinking about it. Your answer can include why this is a "trick question.") (3 pts) – There is no change. Basal Metabolic Rate is the bottom line cost of being alive rate. The couch-potato rate. All activities raise the bird’s metabolic rate above the BMR and it’s this difference that tells up how much something, like laying eggs, "costs."
- What’s the white stuff in bird droppings? (2 pts) Uric acid crystals (not concentrated urine).
- What is its evolutionary significance-why is it important for birds? (3 pts) water conservation
- Give an example of countercurrent mechanisms in birds.
Explain what is conserved and how this happens. (4 pts) –
arterial blood (had to laugh – and give credit- when an ROTC
student had a Freudian slip and wrote "artillary" blood) passes
right next to venous blood. The arterial blood warms the venous
blood, conserving heat. In the nasal passages, heat and moisture
are conserved.
- (5 pts) There are two major antagonistic flight muscles in
birds.
- What are "antagonistic muscles"? muscles that work "against" each other. One moves a limb in one direction, the antagonistic muscle move it back.
- Where does the muscle that elevates the wing originate? Sternum
- Where does it insert? Head of the humerus (not "humerous," which I guess is the funny bone?)
- What’s unusual about this? You’d expect the muscle to originate on the back.
- How does this unusual arrangement help birds fly? Keeps the center of gravity low.
- (3 pts) Flight is very energetically demanding, much more so than locomotion in non-flying mammals. Yet in balance, birds are more efficient than mammals when we calculate km/unit energy ("mpg"). How come? – flight is faster than walking or running, so the birds go a lot farther/unit energy expended.
- How would we determine whether the Barred Owls nesting in suburban Charlotte are a source or sink population? What data would you collect and what results would tell you that the suburban birds are a source, rather than a sink? (5 pts) - measure mortality rates through banding studies and count how many young are produced. If reproduction>mortality, it’s a source population.
- (3 pts) How can taking eggs from an endangered species increase its reproductive output? – removing the "insurance" egg, that wasn’t going to survive anyway, can double the reproduction for a population. If the 1st egg doesn’t hatch, you can replace it with the egg you took. If it does survive, you raise the young from the egg you took and release it into the wild.
- List 5 characteristics that are associated with species of special conservation concern—traits that make species vulnerable to extinction. I’m not looking for sources of mortality (hunting, feral cats, communication towers, etc.), I’m looking for qualities in certain species of birds—some aspect of their natural history--that make them vulnerable. (5 pts) – large size, low pop size, restricted range, top-order predators, good taste, good looks, etc.
- What US state is the hands down winner in the Most-Endangered-Species contest? (2 pts) Hawaii – I think only 1 person got this!
- Of the 100+ extinctions that have occurred since 1600, one factor has played a prominent role in over 90% of them. What is it? (4 pts) – invasive species.
- Why did only 4 species out of 160 breeding in the forests of eastern North America go extinct when the forests were almost completely cleared in the last 2 centuries? (3 pts) – The forests weren’t cut down all at once, so species could find a place to nest in uncut forest ahead of or in regenerating forest behind the wave of deforestation.
- List one abiotic and two biotic problems associated with habitat fragmentation. (No need for a long explanation—just name the issues) (3 pts) – abiotic= changes in microclimate due to edge effects, biotic=increase in brood parasites, nest predators, smaller population sizes, etc.
- Match the endangered species with a conservation strategy
that has been most important in that species’ recovery. More
than one strategy has been used for some of these, but one has
been most important for each. (5 pts) (Prefered answer first)
_C_Peregrine Falcon A. Habitat management
_A_ Kirtland’s Warbler B. Safe Harbor Program
_C/B/D_California Condor C. Captive breeding/reintroduction
_B/A_Red-cockaded WP D. Non-essential experimental population designation
_E_Thick-billed Parrot E. None of the above
- Passenger Pigeons were probably one of the most abundant birds on earth and yet they were driven to extinction in just a hundred years or so. Two factors made them particularly vulnerable. What were they? (One was in the list of traits that make birds vulnerable that we discussed (and hopefully you wrote down on a question above), one was not.) (4 pts) – Good taste (see above) and their gregarious, colonial nesting.
- DDT saved millions of human lives by killing mosquitoes that carry malaria. It’s overuse as a kill-all insecticide led to serious environmental damage. The populations of some birds of prey were reduced so far they had to be put on the endangered species list, while others were not affected at all. What made some types of birds more vulnerable than others? (4 pts) – Species higher up the food chain are more vulnerable.
- Habitat corridors: (6 pts)
- What are they? A strip of habitat that connects habitat patches
- What good are they? Permit individuals to move from patch to patch, thus effectively increasing the amount of habitat available.
- Why might they be detrimental? Might enable predators, parasites, or disease to spread from one patch to another.
- From the list on the right, match a conservationist
associated with each of the following approaches to wildlife
conservation: (3 pts)
- _4_Transcendental/Romantic ethic 1. Gifford Pinchot
- _1_Resource Utilization ethic 2. Aldo Leopold
- _2_Evolutionary-Ecological Land ethic 3. Roger Tory Peterson
4. Thoreau
5. Ted Parker
- The equation below models heat loss (HL) in a
bird as a function of insulation (I), ambient temperature (TA)
and body temperature (TB). Explain how birds can
manipulate each of the three factors on the right side of
the equation to reduce heat loss. (3 pts)
HL = (TB – TA)
I
TB – Lower body temp.
TA –Move to a warmer place
I –Increase insulation by fluffing out feathers or molting in more down.
- Which two of these species are helping save the old-growth
forests of the Pacific Northwest? (4 pts)
- ___ California Gnatcatcher
- ___ Red Knot
- ___ Ivory-billed Woodpecker
- __x_ Spotted Owl
- __x_ Marbled Murrelet
- Isotope ratios in feathers can be used to determine where a
bird was when it grew in those feathers. Which one of the
following is true for a Neotropical migrant arriving on the
breeding grounds in May: (3 pts)
- ___ All feathers (flight and contour) would have isotopes indicative of where the bird overwintered.
- __x_Body feathers would match the wintering grounds, and major flight feathers would reflect the breeding ground.
- ___All feathers (flight and contour) would reflect conditions from the breeding grounds.
- ___Body feathers would be from the breeding grounds and flight feathers from the wintering area.
- ___You can’t tell.
- Habitat fragmentation appears to be a problem for Neotropical migrants. So Wood Thrushes should do really well in the vast Great Smokeys National forest in western North Carolina, yet they are not reproducing well. What other environmental issue is causing problems for them and how is it affecting reproduction? (3 pts) –acid rain causing snail populations to crash so Wood Thrushes aren’t getting enough calcium to make eggs.
- White-crowned Sparrows wintering in California were captured and released in New Orleans. They had never been east of the Rockies and yet they found their way back to their breeding grounds in Alaska. The next winter, those birds were captured and released in Maryland. They once again found their way back to Alaska. Is this an example of orientation or navigation? (3 pts) – navigation-they have a destination in mind and correct for their current location to find their way back to Alaska.
- Why don’t birds have a precise 24-hour circadian rhythm? The earth has been making one spin per 24 hours for all the millions of years that birds have been in existence, so they should have been able to have worked this out by now. What gives? (3 pts) – day length changes during the year or as birds migrate across latitudes, so they have to reset the circadian rhythms all the time.
- How can taking eggs from an endangered species increase its reproductive output? 3 pts -- Oops.
- How can a bird’s song have more than one meaning? Give an example. (4 pts) – the same song could mean that a male wants to mate, if a female hears it, while it would mean "no trespassing" to another male.
- True or False? (4 pts)
__T_Short, abrupt calls covering a broad frequency range are easy to locate.
__F_Communication is said to have occurred when a recipient hears the song from another bird.
__F_Birds vocalize using their larynx, located at the junction of the two bronchi.
__F_Song learning is unique to the order Passeriformes.
- Some types of calls or songs are easy to locate, some are not. Either with songs or calls, explain a situation when a bird would use a locatable song/call and when the same individual would use a hard-to-locate song/call. (4 pts) – If you’re looking for a mate, you want to be locatable. If there’s a predator around you MIGHT not want to be located. Sometimes you do want to be located so you and you buds can gang up on the predator and mob it in the hopes of driving it out of your home range.
- (5 pts:1/1/3) Carotenoid pigments:
- What are they? – pigments made by plants mostly, precursors to vitamin A, etc.
- Why are they physiologically important? Antioxidants help take care of dangerous free radicals, especially in embryos.
- Why do they show up in so many male birds’ plumage or soft parts? Signal to the female that the male is healthy.
- Why are conservation biologists beginning to collaborate
with economists? 3 pts – We need to do cost/benefit analyses
to justify conservation efforts. How much are ecosystem services
worth to society? What’s the value to society of having National
Parks? I gave credit if you said that conservation is expensive
and we need to raise lots of money.
The following 3 are from the questions you submitted to me at the beginning of the semester—Things you’d always wanted to know about birds. You should be able to answer these 3 now:
- (3 pts) How do birds copulate? Sperm passed from cloaca to cloaca.
- (3 pts) Why are there some birds that can’t fly? Why would it be advantageous for birds to lose this ability? – flight is very expensive. If you don’t need it, don’t do it.
- (3 pts) Why don’t birds have teeth and how do they "chew" their food? Teeth lost as a weight-reduction adaptation. Some birds swallow stones to help grind food in their muscular gizzard.
- What was the most surprising thing you learned about birds this semester? (5 pts) – whatever! The most surprising thing I learned was how females "communicate" to their young via testosterone in the eggs. That was news to me.
- Bonus points! Spell Dr. B’s last name. (2 pts) – Bierregaard. Funny how the people who didn’t need the points were mostly the ones who got this right! And not many did.
If you have the energy to respond, what did you think about the Twitter exercise?
A couple of you were annoyed at having to open an account, but almost all enjoyed and found value in the exercise. I think my favorite comment was that the things that the student put in her tweets were the ones she remembered the best.
I used to think Twitter was really dumb, and I still do if you’re just telling the world that you just ate your breakfast, but I see a real value in it if it’s used creatively.