Friday, June 28, 2013

Eurasian Tree Sparrows; A St. Louis Specialty

St. Louis is home to an Old World Sparrow that normally resides in Europe, the UK as well as China, and Japan. I'm talking about the Eurasian Tree Sparrow (Passer montanus). On April 25th 1870, Carl Daenzer and a Mr. Kleinschmidt released 20 Eurasian Tree Sparrows and a variety of other non-native finches in Lafayette Park.  German immigrants largely comprised this part of St. Louis and it was popular during this time period to release European birds in the hopes the introduced birds would control the existing insect population and give the immigrants a little taste of home in their new city. The Eurasian Tree Sparrows were the only birds that survived the release and quickly established a breeding population concentrated near the breweries in south St. Louis. 

It is speculated that the initial success of the Eurasian Tree Sparrow was due to the absence of their aggressive cousin the House Sparrow, which did not arrive in St. Louis until 1878. Once the House Sparrow reached St. Louis, the Eurasian Tree Sparrow population boom slowed but the species extended their range to the Illinois cities of East St. Louis, Alton, Grafton and Belleville, all within about 20 miles of their original point of release.

Today small colonies can be found in the City of St. Louis, Ladue, North St. Louis, Florissant, and east St. Charles County. There are now Eurasian Tree Sparrow colonies in Iowa as well. The first sighting of a pair of Eurasian Tree Sparrows was at West Branch in Cedar County Iowa in March 1987. There were no records for 2 more years, and then 10 birds were found in Des Moines County in December 1989.  A pair of Sparrows nesting was confirmed in Burlington in 1993. The Eurasian Tree Sparrow currently has breeding populations in Lee, Des Moines, Louisa and Muscatine counties
Adult Eurasian Tree Sparrow
A several years ago, I assisted UMSL on a study of Eurasian Tree Sparrows and their cousins the House Sparrows. Their findings suggested that Eurasian Tree Sparrows are homebodies and rarely migrate more than a mile from where they hatched. This could explain why their population has not spread across North America in the same manner as House Sparrows and European Starlings. But there are always the intrepid explorers among the colonies who do wander outside their point of origin and it appears they are following the path of the Mississippi River.


 Eurasian Tree Sparrows are social birds that prefer open fields with shrubby vegetation, especially agricultural areas. These ground feeding birds primarily live on a diet of weed, corn, millet, wheat and sunflower seeds, grass seed and seed shoots but feed their offspring a diet of insects and arachnids during the spring and summer months.
Breeding season begins in April for the Eurasian Tree Sparrow and ends in July (Baicich and Harrison 1997). These birds are cavity nesters, using tree holes, nest boxes or other man-made structures to build their nests.
These birds create an orb-shaped nest with the outer layer composed of coarse grass material and the inner portion lined with down and finer vegetative matter. Eurasian Tree Sparrows can have up to 4 broods per year, though 2-3 broods is the average. Each clutch consists of 1-8 oval eggs (but the average is closer to 4-5 eggs) and incubation lasts 11-14 days. The young fledge around 12-14 days.
 

Eurasian Tree Sparrow chick I banded last summer.
The House Sparrow (Passer domesticus), is an aggressive nest competitor with the Eurasian Tree Sparrow and will displace the latter species from a given habitat. Though both birds are able to adapt to many habitats, the House Sparrow appears to prefer urban areas while the Eurasian Tree Sparrow will occupy more rural, agricultural areas.  However, the Tree Sparrow will move into parks and suburban areas when pushed out of their preferred habitat by their House Sparrow cousins.           

I do know from personal experience that Eurasian Tree Sparrows do visit bird feeders and inhabit backyard nest boxes. Be on the lookout for that little sparrow with the black dot on its cheek.
 

Wednesday, June 26, 2013

The Prairie in June

Phenology is the study of biologic events (such as flowers blooming and birds migrating) in relation to the seasons. I have been working on a restored prairie for the last several years and have enjoyed watching the changes that come with the seasons. For the next year, we'll take a look at what's going on in the prairie once a month.

There are a few flowers in bloom:
Common Milkweed

 Common Milkweed is a host plant to Monarchs. The butterflies lay their eggs on these flowers and the caterpillars eat the leaves. This fragrant flower can be found in prairies, glades and abandoned fields.

Queen of the Prairie

Queen of the Prairie begins to flower in early to mid-summer and is a great plant for the garden.

Slender Mountain Mint.
Slender Mountain Mint.













The Slender Mountain Mint is just beginning to flower this month . Such beautiful, delicate flowers.















And with the flowers come the insects. The Ants were busy on the Common Milkweed, Bees collecting pollen, and Dragonflies hovering above. The Butterflies are making their presence known, and the day's heat had them flying fast. If you look closely at your surroundings, you will find smaller butterflies, such as the Sootywings.

Common Sootywing
Today I watched a Common Sootywing chase a bumblebee off of a White Indigo Plant. The bumblebee was much larger than the butterfly. 

Eastern Tailed-Blue
Eastern Tailed-Blues are tiny butterflies that are often found in gardens and their favorite plants are alfalfa and clover.

I found this mystery fly while walking today. I have no idea of the species.
Mystery Fly
Mystery Fly
Look at the eyes on this insect!
I also encountered several garter snakes today.
 These common snakes will live in a variety of habitats, but they do prefer areas near water. The prairie edges Deer Creek, creating a haven for the garter snakes. Garter Snakes eat frogs, tadpoles, toads, salamanders and earthworms. They occasionally eat mice and smaller snakes.

I'm looking forward to the treasures that will be found on the prairie in July.

Thursday, June 20, 2013

Snakes alive!

There are many myths and misunderstandings surrounding snakes, and this misinformation not only gives these reptiles a bad rap, but needlessly jeopardizes their lives. There are 2400 snake species worldwide with 52 species residing in Missouri, 5 of which are venomous.

Snakes are members of the Class Reptilia, a group that includes turtles, alligators, crocodiles, and lizards. The reptiles are cold-blooded animals, which means they rely on the heat of the environment to warm their blood. Snakes move faster in warmer temperatures and slower when it is cooler. Snakes and other reptiles will often lay on a flat surface, such as a rock, to bask in the sun to increase their metabolism.

A snake's backbone consists of 200 - 400 vertebrae and special muscles that allow for flexibility and the ability to move. There are a number of different ways snakes can move. Some move forward by a side-to-side movement, or in a straight line by literally walking on their ribs. Most snakes use plants, rocks, sticks and other natural irregularities as shove off points. All snakes can swim.

Snake bodies are covered with scales. Without this protective armor, snakes could not move over rough or hot surfaces like tree bark, rocks and hot desert sand. Their scales are nearly waterproof and help keep water out when wet. Rough belly scales allow the snake to keep their grip on branches and push off surfaces when they move.
 Snakes can hear low frequency sounds and feel vibrations. That's why snakes often sense your presence long before they see you. They have heat sensors in pits on the sides of their faces or on their lips. These heat sensors allow snakes to successfully hunt their prey in complete darkness.

Snakes must swallow their food whole, and their jaws are adapted for this method of eating. Snakes can move their upper jaw away from their lower jaw and the left side of their lower jaw from the right side. This expandability, due to extremely elastic muscles and ligaments in the throat and between bones in the jaw, allows snakes to swallow animals up to 3 times the diameter of their head. The snake's teeth also help it to swallow. The teeth are sharp and curve toward the rear of the mouth. While swallowing their prey, the curved teeth help in walking the snakes meal down their throat. Because they can eat such huge meals at one time and are cold blooded, snakes don't eat as often as other animals. During times when food is scarce, most snakes can get away with eating just a few times a year.

Some snakes eat insects and insect larvae, fish, frogs, tadpoles or crayfish, rodents, small birds and their eggs. Their food choices play an important role in the food chain. They help to keep the populations of unwanted animals, such as rats and mice, under control.

Shedding is an important process in the life of a snake. Young snakes will shed every four or five weeks during the summer, whereas adults may shed once every six or eight weeks during that same time period. Rattlesnakes shed 2 - 5 times in a year and a new segment is added at the base of the rattle at each shedding. Determining the age of a rattlesnake by the number of segments in their rattle is not possible because old segments weaken and may break off of the rattle.

About half of Missouri's snakes lay eggs; the rest give birth to fully developed young.

Females will select rotten logs or stumps, leaf litter or sawdust piles in which to deposit their eggs. These eggs are elongated and have a tough, leather shell. Some egg-laying snake species are black rat snakes, bullsnakes, kingsnakes, rough green snakes.

The snakes that give birth to fully developed young are water snakes, garter snakes, brown snakes copperheads, cottonmouths and rattlesnakes.

A few years ago, I came across an Eastern Hognose Snake (Heterodon platyrhinos). As the name implies, the snout looks something like a hog nose.
This species of snake live around sandy areas or open woods with loose soil.  The Hognose Snake has an interesting way of defending itself against perceived danger. When threatened, this harmless snake will spread its neck like a cobra and hiss. It is not uncommon for this snake to roll over and play dead. These snakes mostly feed on toads but are also known to eat frogs or salamanders.

Every summer without fail, I come across Black Rat Snakes (Elaphe obsoleta obsoleta).
These snakes live in a wide variety of habitats: rocky, wooded hillsides, near rivers, in or around farm buildings. Black rat snakes are known for  their remarkable ability to climb up trees. Their diet mainly consists of rodents, birds and bird eggs.

I've recently learned that newly hatched black rat snakes look completely different from their adult counterparts.
These young snakes are tan to gray with distinct black or dark brown blotches along the back and sides of the body. There is a black band on the head that crosses from eye to eye and extends down at an angle toward the mouth. The colors gradually change as the young snake matures. The characteristic black color doesn't appear until the snake is 2 years of age.

All of Missouri's venomous snakes are pit vipers, which means they have an opening on each side of the head, called a sensory pit. A pair of hollow fangs are located on the front of the upper jaw. In daylight these snakes have eyes with vertical pupils (like a cat). Harmless snakes have round pupils.
 
Missouri Department of Conservation.
If you are squeamish about snakes, there are ways to avoid encounters, or at the very least, alert the snake to your presence so that it can begin to make its escape before you notice it.

1) If you can help it, avoid wet habitats such as swamps, wetlands and marshes.
2) It's a good idea to wear thick rubber boots or hiking boots that cover the ankles when walking on trails. These will protect your feet, ankles and lower legs.
3) Snakes are especially fond of rocks and logs. When walking, never place your hands or feet under large rocks and logs. On that same note, it is also a good idea to step on those rocks and logs before walking over them.
4) Piles of discarded wood, scrap corrugated steel roofing, burlap, slabs of bark, and rock piles provide hiding places for snakes and their prey. Remove these objects if they are around your yard.

And ease your mind with these facts on snakebites. A snake rarely will go out of its way to attack you. In fact, most bites occur when a person is trying to handle or kill a snake. Every year in the US, 8000 people are bitten by venomous snakes, but only a dozen die from these bites. By comparison, 120 people die each year from bee stings and 150 people die from lightning strikes.

It is possible to appreciate these incredible animals from a distance. Snakes will rarely, if ever, approach you. If you respect their space, the snake will respect yours.