A Day in the Life of a Biology Assistant in Yosemite National Park

I am holding a radio telemetry antenna to track great gray owls

A Day in the Life of a Biology Assistant in Yosemite National Park

As an intern for the Mosaics in Science Internship at Yosemite National Park, my job description has the title of Biology Assistant. The title biology assistant, however, can encompass many responsibilities, so I am here to help you ponder the question:

I am holding a radio telemetry antenna to track great gray owls

What does the day of a biology assistant

in Yosemite National Park look like?

I am a field technician for the great gray owl ecology project by the National Park Service and the Institute for Bird Populations. A project whose mission is to study the great gray owl ecology and habitat use in Yosemite National Park. One of the parks goals is to find solutions in reducing owl mortalities, especially those related to vehicle collisions. This has proven to be difficult since visitors usually drive at high speeds through foraging or nesting grounds of one of these great gray owls without realizing it. As a field technician I have two main responsibilities: radio telemetry setup and vegetation data protocols.

Radio Telemetry Setup: Tracking the Owls

Radio telemetry setup consist of field visits to 4 different sites, each containing one great gray owl, except for one site which contains a pair sharing the same home range. This would give us a total of 5 tagged great gray owls out of the estimated 150 population size in the park. For security reasons, locations cannot be disclosed to the public. Using radio telemetry equipment as the one in the image below. we can track owls in their feeding grounds. 

Great gray owls are mostly, well, gray, and can easily camouflage with the tree bark. Here is an example of a great gray camouflaging.

Once the owl is visually spotted, we observe from a distance and memorize the trees or sites where he was perched. Perch sites such as trees and branches will be flagged to be used as our study sites, called “used habitat plots”. The GPS transmitters called PinPoint GPS/VHF are transmitting from 1pm – 7pm every other week, giving us a weekly window to grab as much perch sites to complete once the transmitter is off. We follow the owl without disrupting its natural behavior. If we feel that we are provoking its flight from us, we will call off the radio telemetry and perform any used habitat plots. Once we have perch sites from a tracked owl, we can start our vegetation plots.

Vegetation Plots: Assessing Owl Habitat 

Each perch site (tree, branch or artificial) will be considered a used habitat plot, each used plot will be studied through its vegetation data to assess the owls habitat. The used plot can be determined as foraging site (hunting), roosting site (resting), or lingering site. If the owl has a hunting attempt, the place where it landed will be treated has a hunting used plot. We will assess the habitat within a 12-m radius plot centered where the owl was perched. Ropes are used to establish the 12-m radius plot.

I am using a Nikon forestry 550 to measure the heigh of a ponderosa pine

I am recording the height of a Ponderosa Pine

Once a used plot is assessed, we will choose another site called available habitat plot, a distance away from its corresponding used plot, but still in a similar habitat. So, say there are 5 used plots, each used plot will have its respective available plot, adding to a total of 10 used and available plots. Forestry instruments like wedge prism, densiometer, and DBH (Diameter at breast height) are used to determine canopy cover and basal area of trees. Understory vegetation assessment is recorded through percentages of different types of vegetation and ground cover percentages. GPS coordinates are taken of the perch site. 

Here are some images of me using forestry equipment to complete vegetation protocols.

Field Equipment

When I go out into the field, I’ll be carrying most of my forestry and telemetry equipment. Here is an image of me alongside my field equipment. 

I am sitting down besides all my forestry equipment lying on the floor

This is all my forestry and radio telemetry equipment

Best Job Ever

I must admit that I have a very cool job. If I am not tracking owls, I’ll be studying the vegetation in their habitats. Besides my radio telemetry setup and vegetation data protocols, I’ve also helped in great gray owl broadcasting stations to document owls coming back to nesting grounds. I am very excited to continue mastering forestry instruments and VHF tracking for avian conservation. As I progress through the summer, I continue to learn about incredible instruments for forest ecology.

I hope this answers the question and gives you a better idea about the day-to-day life of a biology assistant in Yosemite National Park.

I am smiling at the camera while Bridalveil Falls is behind me

I’m grateful for the Mosaics in Science Diversity Internship for giving me the opportunity to work with experts and grow as a future ecologist and professional of the National Park Service.

Image credits are given to Vishal Subramanyan

Instagram: vishalsubramanyan

1 Comment
  • Dustin Garrison
    Posted at 09:44h, 05 July

    Great post!