Questions Answered & Connections Created: A Scientific Collaboration with VINS & Landmark College

Written by Grae O’Toole, Director, Center for Wild Bird Rehabilitation (she/her/hers)

VINS is excited to announce a new research collaboration with Landmark College located in Putney, VT. Professor Emily Curd Guswa visited the VINS Nature Center in the fall 2021 and noted that many of VINS Ambassador Birds are listed as “sex unknown.” This got her thinking about the class she teaches, Principals of Biology, and about working with VINS to determine the sex of these birds.

Why can’t VINS determine the sex of some of these birds? Surprisingly, it is very difficult to tell if certain avian species are male or female for a few reasons:

  1. There is generally a minimal difference in plumage (feather) coloration
  2. All reproductive organs are found internally
  3. They tend to behave similarly outside of peak breeding season.

There are some subtle ways expert bird banders can determine sex in the field using various physical measurements of the face and legs and noting subtle feather pattern differences. Our Center for Wild Bird Rehabilitation Staff is unable to acquire many of these measurements because the birds received are injured and stressed, so minimizing our contact with them as much as possible is our goal. 

Though there are size differences between males and females among many avian species, with females tending to be the larger of the two, determining sex based on that can be tricky. The problem with relying on this identifier is there is a great deal of overlap and sometimes what was thought to be female because of its large size was just a very large male or vice versa.  Hence why many VINS ambassador birds are labeled with “unknown sex”.

How can we know their sex for sure? Enter Professor Emily Curd Guswa.  Professor Guswa teaches a class called Principles of Biology at Landmark College.  This is an introductory course for science majors offering studies into life at the cellular level.  As part of their course, she teaches two classes of roughly 21 students to use gel electrophoresis on feather samples to determine the sex of birds.  This was a fantastic opportunity for VINS to learn more about our rehabilitation patients and ambassador birds and Landmark College students to learn how to properly run gel electrophoresis tests and interpret their results.  Below you will find an infographic describing the process by which these results are obtained.  

Infographic created by Emily Curd Guswa

Knowing this information about these birds can potentially help staff make better decisions regarding their care.  For example, despite living alone, some of our birds lay eggs – this only happens when the bird feels very comfortable with their surroundings and other environmental factors are just right. If we know that one of our birds is female and breeding season is occurring, we may change her diet regime to ensure that the bird gets the extra nutrients it may need that are now being used to grow an egg.  This also helps staff interpret blood work results – depending on whether or not a bird is male or female may indicate if a certain blood value is abnormally high or low. Staff is then better able to make care decisions based on those results.

Why is important to know the sex of birds out in the wild?  Knowing the sexes of various species is important in ecological studies.  Ecologists can glean more information about how male and female birds may use their environment, says Guswa, which could lead to new conservation initiatives and plans.  For Professor Guswa, running these samples gives her students the tools they need for future careers in molecular studies.

Professor Guswa’s students will be running these tests in the coming weeks and VINS staff is anxiously awaiting to hear the results.  In April, Landmark College students will visit the VINS Nature Center to meet some of the birds they sampled to better see the full scope of their work.  

VINS Staff is so excited to continue collaborating with Landmark College in the future with not only our ambassador birds but our rehabilitation patients as well.

The birds being testing for sex determination. Top left to bottom right: Bridport (Rough-legged Hawk), Hawaii (Peregrine Falcon), Bloomfield (Red-tailed Hawk), Randolph (Turkey Vulture), Wyoming (Ferruginous Hawk), Aurora (Barn Owl), Poultney (Turkey Vulture).

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