Fish Mark and Recapture

01/05/2016 Eric Hanson Leave a comment

When working with a post doc student from North Dakota State University, we studied the life history of the endangered Mohave Tui Chub, we conducted several mark and recapture studies to determine the population on several bodies of water. The two main ponds we focused on were, Lake Tuende and MC Spring on the grounds of the Desert Studies Center at Zzyzx, CA.

mtc — A very large example of the Mohave Tui Chub

We clipped the right pectoral fin on all of the fish we caught in our minnow traps one day, and repeat the experiment the next day to see how many individuals we recaptured. To determine what the population is, you multiply the number of individuals marked the first day by the number of animals captured on the second visit divided by the number of marked animals captured the second day (See wikipedia article for math notation).

Skills

Avian Influenza (AI) Monitoring

01/04/2016 Eric Hanson Leave a comment

When we were in close proximity of the ducks due to rocket netting or trapping, we wanted to get as much information as possible in the shortest amount of time. One of the things we were able to test for was Avian Influenza (AI) with APHIS, the animal and plant health inspection service with the US department of agriculture (USDA). We did pharyngeal and cloacal swabs on a random sampling of the birds being handled. These swabs were put on ice and shipped overnight to the closest USDA testing facility.

Skills

arcMap and arcView

01/03/2016 Eric Hanson Leave a comment

This software is used by most Geographical Information Systems (GIS) professionals. I’ve used this software to measure wetland area, random point intervals for survey work, and georeferencing. If you are interested in seeing a brief introduction to arcMap, please view this short video.

I used arcview on handheld Trimble GPS units to locate points in the field for the belt transect surveys, and also to locate areas for ground cover analysis.

Skills

Aluminum and Incloy Waterfowl Leg Banding

01/02/2016 Eric Hanson Leave a comment

Aluminum bands are the go-to for bird banding, but there was a new alloy called incloy that we were putting on larger waterfowl. Even using a banding pliers, it was hard to get them to crimp right without having to adjust the roundness of the band. They always wanted to overlap.

incloy1 — Incloy band and banding pliers

waterfowl banding — Incloy band being placed on a leg

Here you can see a standard aluminum band placed on a leg. The identifying number allows us to track the migration of the birds, but relies on hunters turning in the band. To combat this, the USFWS partnered with Ducks Unlimited are placing green reward bands on only Mallard ducks.

duckbanding — For aluminum bands, a needle nose pliers worked the best

Below, you can see the standard device used to hold the different sizes of bands. This allows us to put a band on any species of waterfowl that will not fall off, even if they are just in their hatch year.

Skills

Benning Style Swim in Traps

01/01/2016 Eric Hanson Leave a comment

Benning style swim in traps are used to sample duck populations. I used them during my time banding ducks. We first baited a site with barley for several days, and once the ducks were acclimated to that site, we erected the trap.

It consists of a vertical mesh net fashioned in an oval shape with the two ends being curved inwards at the bottom to allow the ducks to swim into the barley feed. As the ducks swim outwards to escape, they reach the inset areas and are forced to bridge the gap and hit the other side of the oval wall. The top is also covered to keep out birds of prey.

My team also set out lethal grip traps for mink and raccoons on predatory paths. This helped limit the morbidity of our Benning traps.

Learning Through Life