Central Valley Entomology

During my visit with the 2nd grade entomologists at Central Valley Elementary School I had the chance to explain how scientist identify the more common orders of insects. I used an insect identification sheet developed by Anita Sanchez to organize our discussion. Unfortunately there was not enough time to cover all seven of the orders of insects that were shown. Here is a review of these common orders of insects, the names entomologists use for them and how these names help us identify them.

Butterflies and Moths – are called Lepidoptera, which means scale wing. If you’ve ever held a moth or butterfly you might have noticed the dusty powder that was left on your fingers. This powder is actually scales from the wings and body of the insect. These scales give color and strength to the wings. Butterflies and moths go through complete metamorphosis, which means they start off as an egg that hatches into a larva. The larva of moths and butterflies are often called caterpillars. The larvae eat and grow. When they are too big for their exoskeleton skin they shed, or molt the skin. Their new skin has room for them to grow. A larva can molt several times before it molts into a pupa. The pupa of a butterfly is called a chrysalis. The pupa of a moth is called a cocoon. Inside the pupa the larva is undergoing a complete change of its body growing all the things it will have as an adult, especially wings. When it emerges from the pupa it will pump up its wings so that they spread and flatten out. When the wings are dry the adult insect flies away to mate and lay eggs.

Bugs – are called Hemiptera, which means half wing. They get this name because the two wings they have are half thick, near the body and half thin further from their body. All bugs are insects but not all insects are bugs. To tell if it is a bug look for a triangle shape on the back of the insect where their thorax meets their abdomen. Bugs undergo what is called incomplete metamorphosis. When a bug hatches from the egg it doesn’t look worm-like, like a caterpillar or maggot. The newly hatched bug looks quite a bit like an insect with three body parts, antenna and six legs. The one thing it will not have is wings. This young bug is called a nymph. The nymph eats and grows. When it is too big for its exoskeleton it molts the skin and emerges a little larger. Upon its last molt it will emerge from the old exoskeleton but now have wings that will spread out, flatten and dry. Once dry the adult bug flies off to look for mates and lay eggs.

Ants, Bees, Wasps and Hornets – are called Hymenoptera, which mean thin skin wing. The hymenoptera have four thin skin, or membranous wings. Many of them, for example ants and honeybees, live in large groups or colonies. In these colonies there is one female that lays the eggs. This is the queen. She will have many daughters, often called workers, that will never lay eggs. In the case of ants these daughters will never have wings. They take care of the queen, feed the larvae and build and protect the nest. At certain times of the year the queen will lay eggs that will grow into adult queens and drones (the males). These adults will have wings. They live in the nest only a few days then fly away to find mates. After they mate the drones will soon die. The queens will start a new nest. The first larvae to hatch will be fed extra eggs that the queen lays for food. After undergoing complete metamorphosis, these first larvae will emerge as worker ants, daughters of the queen, that will now take over building and caring for the nest and all the ants living in it. The queen will spend the rest of her life laying eggs. Some queen ants can live up to 10 years and lay a million eggs in their lifetime.

Flies – are called Diptera, which means two wings. All flies have two wings. Some flies look like bees, yellow bodies with black stripes. Some bees look like flies. The way to tell them apart is to count their wings. Bees have four wings. Flies have two wings. Many insect have fly in their name but are not really flies. Generally speaking if the name is compound, butterfly, dragonfly, mayfly, the insect is not a true fly or dipteran. True flies will have names that are not compound such as house fly, deer fly or black fly. The flies go through complete metamorphosis. The larvae of flies are called maggots.

Dragonfly – are called Odonata, which means toothed. The dragonflies get this name for their predatory behavior, eating many small insects and other animals, both when they are nymphs in the water and adults flying around in the air. One of their favorite foods is mosquitoes. I have watched dragonflies at my pond chase and catch deer flies in mid-air. Dragonflies are not true flies. They undergo incomplete metamorphosis.

Beetles – are called Coleoptera, which means shield wing. The beetles have four wings, two for flying and two that serve as shields that protect the flying wings. When a beetle takes off it lifts open it’s shield wings, unfolds it’s flying wings and flies off. When the beetle lands it folds up it’s flying wings and then closes down it’s shield wings. When the shield wings are closed they meet in a long line down the back of the beetle’s abdomen. The best beetle to see this happen is the lady bug (notice that the lady bug is actually a beetle called the lady bird beetle – it does not have a triangle shape on it’s back like the true bugs, the hemiptera). Beetles go through complete metamorphosis. Beetle larvae are called grubs.

Grasshoppers and Crickets – are called Orthopter, which means straight wing. They get this name because adult grasshoppers have wings that are folded like a hand fan and thus appearing to be straight. Grasshoppers undergo incomplete metamorphosis, hatching out of the eggs as nymphs that look like little tiny grasshoppers. We caught one of these nymphs in our entomology expedition outside.

These seven are among the more common orders of insects. There are about 28 orders of insects. I say about because scientist do not all agree on some of the orders of insects. Some scientist want to combine some orders, while other scientists think it is best to keep them separate. Some of the other orders of more familiar insects include mayflies (Ephemeroptera), fleas (Siphonaptera), cicadas (Homoptera) and earwigs (Dermaptera).

Spiders are not insects. They have eight legs and two body parts (a cephalothorax – which means head-thorax and an abdomen). Entomologists study spiders for several reasons. One reason is that they are relatives of insects. Spiders and insects are arthropods. Other arthropods include centipedes, millipedes and crustaceans (crabs, lobsters, crayfish and shrimp). All arthropods have exoskeletons that are shed or molted when the animals outgrow them. Another reason entomologists study spiders is that where ever you capture insects you will also capture spiders. That is because spiders prey upon insects (although there are some insects that turn the dinner table around and eat spiders).

Insects are the most numerous of all animals. They live all around us, even in our houses. That means there are many insects that can be studied without have to travel far. You can study ants on the playground, beetles in an old rotting log, or caterpillars on leafy branches. When you do these studies you are being an entomologist.

2009 Landis Arboretum Spring Hawk Watch

Every year I start off the Landis Arboretum Family Programs (see http://www.LandisArboretum.org) with a Spring Hawk Watch. This year’s watch looked to be a great one, with a clear sunny day and temperatures in the 70’s predicted. It turned out to be a wonderful day to be outside, although there weren’t as many hawks as hoped for.

The Arboretum looks out to the east and south over the Schoharie River. With the north flowing river being a natural migration corridor for hawks and its incredible views the Arboretum is a nice place to catch glimpses of hawks on their northward journey. Unfortunately today didn’t provide as many hawks as in the past. I am not sure that the unseasonably warm weather was to blame. Actually it’s more likely the steady winds from the west may have been more the reason. In any case there weren’t as many hawks as we’ve had on good days in the past, but as the saying goes, “A bad day birding beats a good day at the office.”

The highlight of the day was the sighting of at least 2 bald eagles, one an adult and the other a juvenile, probably a second year bird. There may have been a third eagle, since a second adult was seen after the first in a different location (both were flying up river – southward). I am wondering if these birds may be nesting somewhere near the Arboretum along the Schoharie River.

We also observed four broad-winged hawks and three osprey. All of these birds were flying strongly northward and thus seemed to be migrating through to their northerly nesting territories.

A number of red-tailed hawks were observed flying about in many different directions. None seemed to be moving strongly northward which makes me think that these hawks are resident birds moving about their territories here in the Schoharie Valley.

Rounding out our observations were a kestrel, a sharp-shinned hawk and a variety of unidentifiable raptors, buteos and accipiters. These unidentifiable hawks were quite a distance out, very likely pushed off the ridge that the Arboretum sits on by the predominately westerly breeze that blew consistently through out the day.

There were many other birds in evidence today, either seen or heard. You can’t spend a day looking for hawks without keeping track of these Arboretum visitors also. The most unusual was a barred owl that was heard hooting. When we first heard it we didn’t believe our ears. So I hooted back and to our amazement it responded. Here is an overall list of the 34 species of birds spotted or heard on this day.

Canada goose
mallard
turkey vulture
osprey
bald eagle
broad-winged hawk
red-tailed hawk
American kestrel
barred owl
red-bellied woodpecker
yellow-bellied sapsucker
downy woodpecker
northern flicker
eastern phoebe
blue jay
American crow
common raven
tree swallow
black capped chickadee
tufted titmouse
red-breasted nuthatch
eastern bluebird
American robin
yellow-rumped warbler
eastern towhee
chipping sparrow
song sparrow
northern cardinal
rose-breasted grosbeak (female)
eastern meadowlark
common grackle
brown-headed cowbird
purple finch
American goldfinch

Ostrander Elementary 2nd Grade Ornithologists Study Owls

Mrs. Busse’s, Mrs. Lazinski’s and Mrs. Dutka’s second grade ornithologists just completed their owl pellet dissection over the last two weeks. Here is what they found:

Busse – 8 pellets dissected; 18 mice, no shrews, no moles and no birds
Lazinski – 10 pellets dissected; 19 mice, 1 shrew, no moles and no birds
Dutka – 9 pellets dissected; 20 mice, 4 shrews, no moles and no birds

You can look at the other schools where I have visited this spring to see what the ornithologists there have found by looking through previous entries in my blog (there is additional information on owl ecology and ornithology studies in these blog entries, as well as the owl pellet data). I do have a few more owl ecology classes coming up before the end of school, so there will be more data add in the near future. Here to date, is an overview of what we’ve found in our owl pellet dissections in my previous school visits this year.

Including the pellets dissected at Ostrander Elementary our total tally is:
212 pellets dissected; 447 mice, 32 shrews, 6 moles, 6 birds

The average number of animals eaten per pellet is 2.3 animals.

Check this blog for more owl pellet data as I complete my ecologist-in-residence programs through to the end of the school year.

Kings Elementary School Owl Ecology/Owl Pellet Analysis

Today I visited the 3rd and ¾ PIE classes at Kings Elementary School in Warwick. We had a discussion on being ornithologists. It focused on how students might do a project to document where three common owls, the Eastern Screech-owl, the Great Horned Owl, the Barred Owl might be found in the Warwick area, including researching the owls’ habitat and calling behavior. This is exactly the kind of work that was done by many volunteer and professional ornithologists to complete the New York State Breeding Bird Atlas project, a multi-year project that was just culminated with the publishing of “The Second Atlas of Breeding Birds of New York State (see link below).

This discussion led to an owl pellet dissection and analysis. We can add this information to the other owl pellet analysis that I have done with other school and get an even better look at what owls - barn owls in the Pacific Northwest, northern California, Oregon and Washington – prefer to eat.

Why west coast barn owls? I do many owl ecology classes in which students take apart many owl pellets. I use many hundreds of pellets every year with all my school programs. It would be impossible for me to get enough pellets from wild owls since the pellets they regurgitate would be found spread all around the forested territories that the owls live in – a wild great horned owl, barred owl or screech-owl might spit out three or four pellets each night, but would likely do so at three or four different locations dispersed about the forest and forest edge environments that they live in. To find several pellets would be lucky, to find hundreds, nearly impossible, even if I were to find several owl nests and get the pellets expelled by the growing young. So, I buy my pellets from Pellets, Inc. (see link), which is a company located in Bellingham, WA. Pellets, Inc. collects barn owl pellets from the areas of northern California through Oregon into the state of Washington.

Why barn owls? When barn owls live in essentially open country areas of farmland or abandoned buildings (especially at the outskirts of towns) they roost and nest in barns, and old buildings like unused factories, churches or houses. After hunting and feeding upon several small prey animals the owls return to the roosting or nesting site and soon regurgitate a pellet. An owl might cough up three or four pellets a night. A family of five or six owls can produce 15 to 24 pellets a night. If someone knows where these roosting or nesting places are they can find many pellets. Pellets, Inc. hires people to visit such roosting and nesting places to collect pellets. The pellets are fumigated to kill moth larva, inspected and wrapped in aluminum foil and shipped out to scientists, teachers, students and naturalists.

Why fumigated? An owl pellet is mostly mammal fur with some bones stuffed in the package. Although the fur and bones are of no nutritional value for the owl there is still food available in the bones and fur. Some species of moth specialize in eating mammal fur – these are the very same moths that get into our closets and eat holes in our wool sweaters, suits and other clothing (after all, wool is sheep or other animal fur). Actually it is the larvae of the moths that do the eating. If a pellet has been lying around a long enough time, a female moth will find it and lay some eggs on the pellet. Larvae will hatch from the eggs and begin to eat the fur in the pellet. Pellets, Inc. fumigates the pellets to kill any moth larvae that happen to be in the pellet. You will sometimes find these dead larvae. They are small, about an eighth of an inch long, and brownish in color. If you look carefully at them you will see the segmented body, including the head and six small legs of the larva. If you find several dead larvae you will also likely find tiny black, sand-grain size specks. This is the frass or poop that the larvae produced when they were alive eating the fur. These larvae are performing the function of decomposers reducing the final remains of dead animals to their elemental parts that will then become part of the soil for plants to use in the cycle of life.

Here are the results of the Kings Elementary School owl pellet dissection:
Mr. Dinoto’s class – rodents, 17; shrews, zero; moles, zero; birds, 1 – 8 pellets dissected
Mrs. Flynn/Mrs. Nachtigal’s classes – rodents, 34; shrews, 2; moles, 1; birds, zero – 18 pellets dissected
Mrs. Parker’s class – rodents, 21; shrews, zero; moles, zero; birds, zero – 9 pellets dissected
Mrs. Kipp’s class – rodents, 20; shrews, 1; moles, zero; birds, 1 – 11 pellets dissected

Totals for all four groups
Rodents, 92; shrews, 3; moles, 1; birds, 2 – 46 pellets dissected

The average number of animals eaten per pellet was 2.1 animals.

Look at the other results for owl pellet dissections that I discuss here on the blog. You can compare these findings or, better yet, add them to the findings to get a better idea of what barn owls of the Pacific Northwest prefer to eat.