Eggs-celent!

With summer well under way, it's the time of year for critters of all sorts to be laying their eggs. Whether bird, reptile, or amphibian, hear are some of the eggs I've come across in the past few weeks.

Killdeer eggs blend in nicely with the gravely areas they make their nests.

Four eggs are in the far right of this picture.

To start off, we have the fine-feathered shorebird, the Killdeer (Charadrius vociferus, "Noisy plover"). This bird doesn't have to be on the coast to be seen, and it is most well-known for its loud and frequent calling. Killdeer are ground-nesting birds, and their eggs are camouflaged for the gravel-like and sandy areas they like to lay. When threatened, a Killdeer guarding its nest will either fluff its feathers and tail to scare animals off, or it will pretend to have a broken wing so as to distract predators from its eggs.

Reptiles have been laying their eggs too. Instead of brooding eggs like birds, reptiles must lay their eggs in substrate that is warm enough to act like a natural incubator. This usually means sunny, dry, sandy areas. This common snapping turtle (Chelydra serpentina, "Snake-like turtle") exhibited an interesting behavior of shuffling her eggs around are depositing them each time. A snapping turtle's clutch can contain between 20-40 eggs.

As you know, I am a big fan of salamanders that breed in vernal pools. The Ambystoma genus of salamanders (Spotted, Jefferson's) laid earlier in April, and their eggs have been hatching over the patch few weeks. Unlike other eggs anywhere else, the eggs of Spotted salamanders have a unique symbiotic relationship with algae. So far, they are the only known vertebrate species that has a symbiotic relationship with algae. These algae, known as Oophila amblystomatis, not only invade the jelly of the egg, but they also invade the embryo and salamander tissue. The salamander benefits from increased oxygen and removal of ammonia waste during development, and the algae benefits excreted nutrients. Much is still not know about this relationship, but is clear that without the algae, eggs develop more slowly, have higher mortality rates, and produce smaller young upon hatching.

Algae covered Spotted Salamander larvae await to hatch at the end of May.

From a few months ago, underwater footage (couldn't help myself)

 of Jefferson's salamander eggs. Notice, they lack the algae their close cousin's have.

References
Kerney, R. (2011). Symbioses between salamander embryos and green algae. Symbiosis, 54(3), 107–117. 

So Long, Winter

It is that fun time of the year where one day is sunny and warm and the next day it snows. While the seasons battle it out for spring's inevitable victory, wildlife are beginning to respond to the changing weather. Birds begin their migrations and add some variety to the resident birds that stayed through the winter. Those animals that hibernated or slumbered in their torpor are stirring. Perhaps my favorite of all is that of the vernal-pool breeding amphibians. Vernal, Latin for spring, describes wetlands that usually only exist during the springtime. These wetlands are typically filled by winter precipitation and snow-melt and are dry and gone by the end of the summer. This ephemeral existence means fish can rarely establish themselves, so amphibians can develop without fear of predation by fish. So, as these seasons change, let us say "see you around" to our winter friends and hello to our spring buddies.

For the first time I tried to point my camera trap skyward, and while it didn't stalk the visitors of my bird feeder quite as well as I had hoped, I did catch some decent photos of the avian folks who spent the winter in the woodlot behind my townhouse. I am still a birding novice, but I did count eight species at my bird feeder this year. All of them are familiar faces to those who put up a bird feeder during the winter. Pictured above we have the black-capped chickadee (Poecile atricapillus,  meaning "spotted black-hair"). These common birds have dynamic brains, where they let old brain matter to die off each autumn so that new neurons can be formed to better match changing conditions. 


We also have the white-breasted nuthatch (Sitta carolinensis) exhibiting the characteristic upside-down nuthatch position. As evidenced by this photo, white-breasted nuthatches visit feeders along with other birds. When the tufted titmouse (the other bird in the picture, Baeolophus bicolor, meaning "two colored little crest") is removed from feeding flocks, the white-breasted nuthatch is much more wary of bird feeders, indicating it relies on other birds to help watch for predators when feeding. Other favorites of mine this year were the dark-eyed junco (Junco hyemalis meaning "winter bird"), the house finch (Haemorhous mexicanus, meaning "Mexican fruit biter"), and the mourning dove (Zenaida macroura, meaning "long-tailed daughter of Zeus"). 


It's also time to welcome our early ectotherms. Here in the northeast, we most notably have the Jefferson's salamander (Ambystoma jeffersonianum) that will begin breeding even when vernal pools have ice covering them. As part of our research on the vernal ponds in the area, we often catch hundreds of Jefferson's salamanders. These salamanders are extremely slimy. The slime they excrete not only deters predators, but it is also thought that they use the slime to communicate chemically with each other. During the mating season, leaving a persistent scent trail may be helpful in courtship. By chance, when checking our traps this season, we found a midland painted turtle (Chrysemys picta marginata) who must of woke up too early!

As you can tell, I recently got access to an underwater camera and am taking full advantage of it. 

References
http://www.allaboutbirds.org/guide/search

Snake, Rattle and Roll Part 2: This Time It's Personal

*Blood Disclaimer: Images from veterinarian surgery below.

A long while ago, I wrote about surveying for timber rattlesnakes (Crotalus horridus) in the Midwest. Last summer I had the opportunity to visit those sites again, although this time it was for a different purpose. Working with a Department of Natural Resource’s contractor, our goal was to survey known rattlesnake populations in an effort to characterize the prevalence and distribution of snake fungal disease (SFD), a recently documented wildlife disease.

Basking amongst the warm rocks. The snake bag was poised and ready!

While scattered reports of the disease have been surfacing over the past several years, SFD is still surrounded by a shroud of mystery. It is currently hypothesized that the fungus Ophidiomyces ophiodiicola (From Greek “ophio” meaning serpent, and “myces” meaning fungus) is the agent of the infection, but the evidence remains unclear. The disposition of a snake does not improve matters. Generally, snakes are solitary creatures, making it difficult to understand how the disease is transmitted. One possibility is transmission during hibernation. In this region timber rattlesnakes have community hibernacula, so the disease may be spread when several individuals come into contact during the winter. Another possibility is that the fungus is ubiquitous throughout the environment and only becomes pathogenic under certain conditions. 

Since long-term population monitoring is rare, and since SFD is so new, it is challenging for scientists to get a clear picture on how SFD is impacting snake populations. Nonetheless, there is compelling evidence that SFD has harmed and will continue to impede snake conservation (Sutherland et al., 2014). Currently, reports of SFD have occurred mainly in the eastern United States. Several snakes species have had reported signs of SFD infection; however, SFD first gained attention due to its impacts on northeastern populations of timber rattlesnakes and eastern massassauga populations in Illinois. Within a single year, SFD played a clear role in the 50% decline of the last New Hampshire population of rattlers in 2006 (Clark et al., 2011). To shed some light on the situation, research is currently being done to understand the disease's dynamics. So, let’s get back to the Midwest!

To avoid being bitten, venomous snakes are 

measured and handled while safely stuck in a tube.

On a sweltering day in June, with the mayfly hatch swarming, we spent the morning hours scouring  prairie hillsides. Whether basking at the edge of cover or hiding under shelf-rock, we found several rattlesnakes during our search. Once we captured them with snake tongs and safely deposited them into a snake bag, we moved to a convenient place to work each individual up (somewhere not at a 45 degree slope!). We determined their weight, length, gender, and body condition. Several snakes looked healthy, but one individual had a conspicuous node on its side. Since SFD causes a variety of skin defects (blisters, lesions, swellings), we took it in to have the node removed and biopsied.

The types of infections caused can SFD can vary greatly, 

from nuisances like this node to severely damaged respiratory tissue.

It was my first time witnessing an animal surgery, and it was enlightening to see a side of wildlife science completely unknown to me. To top it off, I got to play honorary veterinary assistant (don’t worry, the trained individuals did all of the important things). Once the snake was calmly anesthetized, the veterinarian carefully removed the node, gave the tissue to the wildlife ecologist doing work on SFD, and neatly sutured the snake’s wound. A day later, the snake was released back at the point it was captured.

This snake can't avoid being stuck in a tube! Here, it enters the

 apparatus to receive a constant air flow that contains the anesthesia.

Throughout the surgery, the snake's breathing and vitals are closely monitored.

Here the dilated pupils indicate that the snake is nice and relaxed.

I just recently learned the node's biopsy came back positive for O. ophiodiicola, so it was considered to be a SFD infection. At this point some might ask, “why let the potentially infected snake back out into the wild?”. Too little is currently known about SFD to know how to effectively combat it. Most likely, if the disease had already infected that one snake, the fungus was present throughout the whole area. Considering timber rattlesnakes are having a tough time in many parts of their range, removing an individual would be more detrimental than releasing the infected snake--especially since the mortality rate of SFD varies dramatically.

The surgery area is prepped.

Doc said "scalpel", so I handed him a scalpel.  

Here, the node has successfully been removed. The tissue was 

then divided and placed in a vial for further analysis.

To finish the surgery, the wound was stitched closed and it was given fluid to rehydrate.

Once the snake appeared responsive from coming out of the anesthesia, it was placed back

in its transportation container.

It was great to re-visit these timber rattlesnake populations once more. I can only hope the researchers working on this project will not only get a better sense of where SFD occurs but also its underlying cause so that proper disease management can be undertaken. 

If you think you have come into contact with a snake that may be showing signs of SFD, call your state wildlife agency. Also, clean your shoes and any other gear with soap and water. Then soak in a 10% bleach solution.

All surveys were done with appropriate permissions, permits, and humane handling protocols.

References

Clark, R. W., Marchand, M. N., Clifford, B. J., Stechert, R., & Stephens, S. (2011). Decline of an isolated timber rattlesnake (Crotalus horridus) population: Interactions between climate change, disease, and loss of genetic diversity. Biological Conservation, 144(2), 886–891. doi:10.1016/j.biocon.2010.12.001

Northeast Partners in Amphibian and Reptile Conservation. 2013. Snake Fungal Disease: Frequently Asked Questions. http://www.northeastparc.org/products/pdfs/NEPARC_SnakeFungalDiseaseFAQ.pdf

Sutherland, W. J., Aveling, R., Brooks, T. M., Clout, M., Dicks, L. V., Fellman, L., … Watkinson, A. R. (2014). A horizon scan of global conservation issues for 2014. Trends in Ecology and Evolution, 29(1), 15–22.

USGS National Wildlife Health Center. 2013. Snake Fungal Disease in the United States. http://www.nwhc.usgs.gov/publications/wildlife_health_bulletins/WHB_2013-02_Snake_Fungal_Disease.pdf