Studies You Can Do at Roost Sites
By Dr. Lincoln Brower
much yet to be learned at the temporary roosts (or "bivouacs")
that monarchs use during migration. How would a person study a site? What
would you do?
up a chair, grab a pair of binoculars and just sit and watch! I'd try
to stay hour after hour, day after day--as long as the monarchs were there.
People can contribute important observations by going with an open mind
and documenting what they see. Science is often done with pre-conceived
ideas, and so scientists can get hung up on their own theories, and forget
to ask "What IS going on here?"
Dr. Lincoln Brower
resting at roost in Minnesota.
A very thorough
ethogram (behavioral description) of the dynamics of roost formation during
the fall migration needs to be documented and published. It is really
amazing how little we know about these critters.
are some of the questions I'd try to answer:
- What time
of day do the monarchs arrive?
- Do they
gather up in the sky and all drop down at once?
- Or do
they arrive gradually?
- How do
they interact as the roost site forms?
- How tall
are the trees? Do they afford protection from the wind?
- Does the
roost-size vary, depending on the direction of the wind?
- Are they
active at night? Can you tell when they go to sleep?
- How long
do individuals stay? (To test, tag and release. See: Mark,
- When do
they depart? Do they all take off the next morning? Or on the next clear
day? Do they gather and wait for the next front to arrive?
- We know
they fatten up as they fly southward, so nectar is important. Can you
spot good nectar areas nearby? How do numbers of monarchs nectaring
compare to numbers at the roost?
- Take videos
of the butterflies as they are forming their roosts and then take the
tapes home and study them carefully. Keep track of the time on the tapes
if possible. There is some complex social behavior going on that might
emerge through thoughtful observations of the tapes. If you can speed
up or slow down the videos when you show them, it could shed even more
light on what is actually happening. Early morning videos--as they wake
up and fly off--would also be very valuable to study.
your observations to Journey South and help document this interesting
aspect of monarch migratory behavior!
of K. Wheeler
behavior, seen when a new monarch joins
the roost. Video
of Sheila Daniels