Sunday, June 23, 2013

Bats in Mazama

Last Friday, here at the North Cascades Basecamp, we hosted students from Central Washington University visiting as part of a wildlife ecology field techniques class with Dan Beck. Arriving in the early morning, Kim and Steve took the students on an introduction to birding walk around the Basecamp property where numerous species were heard and identified. 

Later in the evening, the students returned for a trip highlight- bat mist netting. What is bat mist netting you may ask (as I did).  Mist netting is an effective and safe way of capturing both birds and bats.   Very lightweight, almost invisible, nylon nets are strung between two poles over a highly trafficked area.  In our case, we strung three nets over ponds, very close to the water's surface.  

Kent and Kim carefully setting up the mist nets

USFWS Wildlife biologist, Kent Woodruff, led the evening and proved to be an excellent source of information.  However, early on he stated that bat knowledge is very limited, especially here in the Methow Valley.  "The answer to most questions about bats is 'I don't know.'"  He attributes the lack of knowledge to the difficult task of these small flying mammals, and to the lack of funding/support for research.  Unfortunately, bats often have a negative association in our society and aren't the cuddly animals that people are willing to support and protect.  While research and understanding surrounding bats is often limited, it is clear that they do play an important role in our ecosystem and are often referred to as a 'keystone' species.

Anticipation grew as the nets were assembled and dusk arrived.  The group of 25 students and Basecamp guests sat patiently and quietly on logs surrounding the ponds and waited for the bats to arrive.  Soon the first bats were spotted and excitement grew as more quickly arrived.  It was clear everyone was enjoying watching the acrobatic show the bats put on but also anxious for the first bat capture.

After 20 minutes of waiting, our patience was rewarded with the capture of the Methow Valley's smallest bat species.  Weighing about the same as a penny, California Mytois bat (myotis californicus) is found along the west coast of America; from British Columbia, Canada to as far south as Guatemala.

The group assembled around Kent as he identified the bat.  He identified our bat by it’s keeled calcar (a cartilaginous spur of the ankle joint that extends toward the tail), small feet, color and facial features.

Pointing out the Keeled Calcar

There are approximately 1100 bat species across every continent (except Antarctica). Here in Washington State we have 15 bats species, 8 of which are currently listed federally as Category 2 Candidates, meaning adequate information is lacking to list them as endangered species. However, it is hypothesized that they should receive that designation.  Across the nation approximately 40 percent of bat species are currently threatened.  

How can you help?

Interested in learning more about Bats in Washington?
Basic facts about bats from the Washington Department of Fish and Wildlife

The recent (and first!) conservation plan for bats in Washington State

Washington Department of Fish and Wildlife Live Bat Cam

Bats Northwest; a non-profit to protect bats through education and research

Wednesday, June 19, 2013

Co-evolution of the red-naped and red-breasted sapsuckers

The red-breasted Sphyrapicus ruber and red-naped Sphyrapicus nuchalis sapsuckers are two woodpecker species that overlap in their range near the crest of the Cascades.  These two species are sympatric, meaning that during the evolution process, they became two new species while inhabiting the same geographic region. Generally speaking in Washington, the red-breasted live on the west side, the red-naped on the east side.   At the North Cascades Basecamp in Mazama, we’ve had the opportunity to observe both species in a cedar and birch grove that is unique to the upper Methow watershed.

This year, a male red-breasted sapsucker was observed late in the winter along the Basecamp trail.  He drummed his broken drum on local snags, showed off his beautiful red head, called his quiet “mewing” call, and even excavated a perfectly round cavity in a birch snag.  A female red-naped sapsucker was often seen in the same area, licking (not drinking) up sap with her barbed tongue, making frequent visits to his territory, and exploring the newly constructed cavity with intrepidation (poking her head up to the entrance but not entering).  Finally in mid-June, after many hours of observation, we saw the red-breasted male and the red-naped female both enter and exist the nesting cavity with food in beak for the hungry nestlings, and he was being a good dad and dropping fecal sacs to the ground as his housecleaning duties ensued.   

These two species of sapsuckers are known to hybridize in south-central Oregon, northeastern California, along the California-Nevada border, and in southern Nevada.  Genetic studies by Johnson et al (1983, 1985) showed that red-naped and red-breasted sapsuckers have the highest avian genetic relatedness ever reported, similar to that found between avian subspecies.  They also found the hybrid F1 generation to produce viable offspring, although it seems that certain F2 backcrossings may have partial sterility issues.  These studies and others confirm that although these two species are nearly genetically identical, there is a low degree of hybridization while encountering each other regularly, and therefore they are still considered as separate biological species. 

It will be interesting to see what our new fledgling hybrid sapsuckers look like, and who they choose as mates into the future.

Ned K. Johnson and Robert M. Zink. 1983. Speciation in Sapsuckers (Sphyrapicus): I. Genetic Differentiation.  The Auk: 871-884.

Ned K. Johnson and Carla Bowman Johnson.  1985.  Speciation in Sapsuckers (Sphyrapicus): II. Sympatry, Hybridization, and Mate Preference in S. ruber daggetti and S. nuchalis.  The Auk: 1-15.