May 302014
 

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The DFW Urban Wildlife iNaturalist Project continues to grow at and amazing rate, and again we have had dozens of great new observations submitted this week. Together we are building a complete and detailed record of the wide variety of wildlife living in and around the Dallas/Fort Worth area!

Below you will find our three favorite submissions for the past seven days. Remember that “favorite” in this case can mean a whole host of different things. When selecting feature images we will be looking for examples of rare or unique wildlife, interesting behaviors or situations, and great photography and compositions.

Graham's Crayfish Snake by taogirl.  Click the image to see the observation details in iNaturalist.

Graham’s Crayfish Snake by taogirl. Click the image to see the observation details in iNaturalist.

This is a great photograph and a great observation. The Graham’s Crayfish Snake is another animal that I have yet to observe in the metroplex. In fact, this is a species of snake that I was not even aware existed. Its a perfect example of the power of iNaturalist to educate and enlighten.

As the name suggests, the Graham’s Crayfish Snake feeds primarily on freshwater crustaceans. According to my reference material, these snakes prefer recently molted crayfish. This is because it takes some time for a crayfish’s exoskeleton to harden up again after a molt. This soft state leaves the crayfish effectively disarmed, and therefore particularly vulnerable to predators.

Here is what Wikipedia has to say about the Graham’s Crayfish Snake and its preferred habitat:

It is a medium-sized snake, measuring an average of 18–28 inches (46–71 cm) in total length, but can grow up to almost 4 feet long in some cases. The maximum recorded length is 47 inches (119 cm).

It is usually a brown or gray color with an occasional faint mid-dorsal stripe. It’s lateral stripes are typically cream, white tan, or light yellow and located from the belly up to the fourth scale row. The belly is typically the same color as the lateral stripes and is unmarked, with the exception of a row of dark dots down the center (rare in specimens).

Regina grahamii occurs along the margins of mud-bottom marshes, oxbow lakes, rivers and streams; particularly likes roadside ditches abundant with crayfish. They typically hide under rocks, logs, and other debris at the waters edge and also spend much time in crayfish burrows.

Thanks for sharing this with us, taogirl! Click here to see all iNaturalist submissions by taogirl.

Viriginia Opossum  by maryejohnson.  Click the image to see the observation details in iNaturalist.

Viriginia Opossum by maryejohnson. Click the image to see the observation details in iNaturalist.

I really love this picture of an early morning Opossum making its way through a natural-looking environment. Over the years I have become so accustomed to seeing these guys in alleyways and in business parks that something like this almost seems to be the exceptional case.

Opossums are North America’s only marsupial. That means that female Opossums have a pouch on their abdomens that they use to carry, nuture, and protect their young. Wikipedia describes the reproductive system and life cycle of the Opossum in this way:

As a marsupial, the opossum has a reproductive system including a divided uterus and marsupium, which is the pouch. Opossums do possess a placenta, but it is short-lived, simple in structure, and, unlike that of placental mammals, is not fully functional. The young are therefore born at a very early stage, although the gestation period is similar to many other small marsupials, at only 12 to 14 days. Once born, the offspring must find their way into the marsupium to hold onto and nurse from a teat. The species are moderately sexually dimorphic with males usually being slightly larger, much heavier, and having larger canines than females. The largest difference between the opossum and non-marsupial mammals is the bifurcated penis of the male and bifurcated vagina of the female (the source of the term “didelphimorph,” from the Greek “didelphys,” meaning double-wombed). Opossum spermatozoa exhibit sperm-pairing, forming conjugate pairs in the epididymis. This may ensure that flagella movement can be accurately coordinated for maximal motility. Conjugate pairs dissociate into separate spermatozoa before fertilization.

Female opossums often give birth to very large numbers of young, most of which fail to attach to a teat, although as many as thirteen young can attach, and therefore survive, depending on species. The young are weaned between 70 and 125 days, when they detach from the teat and leave the pouch. The opossum lifespan is unusually short for a mammal of its size, usually only two to four years. Senescence is rapid.

Nice work, maryejohnson! Click here to see all iNaturalist submissions by maryejohnson.

Reakirt's Blue by taogirl.  Click the image to see the observation details in iNaturalist.

Reakirt’s Blue by taogirl. Click the image to see the observation details in iNaturalist.

This gorgeous photograph is of the tiny but beautiful Reakirt’s Blue butterfly. Small insects like this one are easy to overlook in the field. But, as is often the case, if you take the time to observe a little more closely an unexpected beauty will be revealed.

The icy blue coloration of the male butterfly’s body slowly transitions to a subtle violet as it moves outward along the wings. The wingtips are bordered with a band of black and one of white. The effect is really quite striking.

It spite of its small size, this butterfly is known to migrate long distances across North America. Here is how Wikipedia describes the habits of the Reakirt’s Blue:

The Reakirt’s Blue (Hemiargus isola) is a butterfly of the Lycaenidae family. It is found in Central America and the extreme southern U.S., isola migrates regularly throughout most of the U.S. almost to the Canadian border, and very rarely into the southern Prairies.

The wingspan is 16–23 mm. Adults are on wing from June to October in the north and all year round in south.

Another great find, taogirl! Click here to see all iNaturalist submissions by taogirl.

Thanks to everyone for their continued contributions to the DFW Urban Wildlife iNaturalist Project. We value each and every submission we get! If you would like to contribute, its easy to do. Just follow the link below, create an account and start uploading your observations and photographs. Be sure to add them to the DFW Urban Wildlife project so that everyone will be able to see them. We look forward to seeing what you have to share!

DFWUWiNaturalistProjectCompact

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