| "Who's Whoo-ing" In Your Backyard? |
| A Citizen Science Study of Suburban Owls |
ABOUT
This project is set up so that people who have little experience with bird calls or field methods can participate.
We think you and your family will really enjoy searching for owls on your property! If you are interested in
becoming a part of the project we would love to have your assistance. Please register via email. This will allow
us to keep in touch with you and send you any important information and updates. Your address will be kept
confidential.
Email: owlcall@mianus.org.
Our survey is very simple. It is based on the repeat-survey methodology of MacKenzie et al. (see citations and
additional details at the bottom of this page). It is vital that everyone follow the same procedures so that data
can be compared.
We are searching primarily for two species of owls in the region (eastern screech owls and barred owls), and
secondarily for one additional species (great-horned owls).
Briefly, a single survey is a matter of playing recorded owl calls for 10 minutes while listening for responses.
These species will almost always respond to a call because they are quite territorial. You then record whether
or not you get a response, that's it.
We think you and your family will really enjoy searching for owls on your property! If you are interested in
becoming a part of the project we would love to have your assistance. Please register via email. This will allow
us to keep in touch with you and send you any important information and updates. Your address will be kept
confidential.
Email: owlcall@mianus.org.
Our survey is very simple. It is based on the repeat-survey methodology of MacKenzie et al. (see citations and
additional details at the bottom of this page). It is vital that everyone follow the same procedures so that data
can be compared.
We are searching primarily for two species of owls in the region (eastern screech owls and barred owls), and
secondarily for one additional species (great-horned owls).
Briefly, a single survey is a matter of playing recorded owl calls for 10 minutes while listening for responses.
These species will almost always respond to a call because they are quite territorial. You then record whether
or not you get a response, that's it.
All you need to do is play a CD of owl calls from your backyard with a boombox, and listen for a response from wild owls. If there is no response, that is
still vital data, and you will still be contributing to the study just as much as a positive response.
There are a few simple standards and procedures that you would need to commit to:
Thank you for your interest!
Some Details on our Methods
If you are interested in the details of our analysis, please see:
OCCUPANCY ESTIMATION AND MODELING by MacKenzie, Nichols, Royle, Pollock, Bailey, Hines
or
Occupancy/Presence website
Here is a brief explanation:
Many times, biologists are looking for a certain species in a number of locations. So they go out and look for it, in any number of ways appropriate to
catching or observing that species (e.g., cameras, traps, nets, tracks, or call surveys).
Usually they find the species in some sites, and don't find it in others. However, in those places that they are not found, the species could really be there
but the biologist failed to find it. This means that whatever method they used (traps, etc.) is imperfect and has a rate of failure.
Scientists can deal with imperfection and failure, if they can estimate what the rate of failure actually is. By doing repeated surveys in a set of locations,
you can estimate not only the places where the species definitely lives, but the places where the species probably lives even if you didn't find it. This
gives you a better estimate of the proportion of the total sites you looked that have the species (e.g., "60% of the places you looked are likely
occupied"). You can also estimate how effective your method is (called the detection probability), e.g., "you have a 80% chance of finding the species
using call surveys if it is actually there."
Once these two measurements are estimated, you can relate both to habitat or other variables. Did your detection rate go up (i.e., was the species
easier to find) when it was warm/at night/etc.? Were they more often found in the woods or in the city? Or, were they just easier to find in the city than in
the woods? In our study we are also interested to see if the two species are found together or do not overlap.
Repeated surveys at every location are necessary, even if you find the species right away. Without the repeated surveys, you could not estimate
detection probability.
still vital data, and you will still be contributing to the study just as much as a positive response.
There are a few simple standards and procedures that you would need to commit to:
- We ask that you agree to survey for eastern screech owls and barred owls. Great-horns are optional.
- We are asking that you conduct 3 surveys in a season for each species. These surveys must be done on different days (you can not do 2 surveys
in a single day for both species or a single species). Even if you find an owl on the 1st or 2nd try, you must complete all 3. This is a vital part of the
analysis and helps us determine how often we tend to miss owls that are really there (see details below).
- The project is divided into 3 month seasons. The seasons are Spring (March - May), Summer (June - August), Fall (September to November), and
Winter (December - February).
- Listen for the entire 10 minutes of the track. In our experience, owls tend to respond around the 7 - 8 minute mark.
- Use the same location for all 3 surveys. Again, in order to determine how often we miss owls that are really there, the same location must be
surveyed multiple times.
- We are asking our volunteers for a total of 6 nights a season (2 species x 3 surveys) from 2009 to 2010. This adds up to 60 minutes a season (10
minutes each survey); one hour over the course of 3 months. You can volunteer for as little as one season if you wish; we hope you will stay for
multiple.
- Only survey for a single species in one night. Even though (foolish?) owls sometimes respond to other species' calls, it is much more likely that
they will stay quiet when they hear another type of owl because the bigger species often prey on the little ones (see below).
- Surveys for each species must be done on different nights
- Barred owls and great-horns sometimes eat the smaller screech and saw-whet owls, so if you play small owl calls after large owl calls, the
small owls will usually stay quiet so they are not found by the larger owl they think is there.
- Similarly, barreds and great-horns may not call after they hear smaller owl calls because they are looking for the small owl they think is there.
- We would also recommend separating your cross-species surveys by 2 or so days, for the same reasons.
- We also stress that the over-use of these calls may disrupt the owl's normal behavior. Please do not conduct more than 3 or 4 surveys a
season. We definitely want our neighbors to be interested in owls and the outdoors in general, and this goal is one of the main purposes of this
project. However, the well-being of the animals is of utmost importance, and we do not (and are sure you do not) want to adversely affect the owls.
- If you detect an owl on your property, please do not start calling them in just for fun. Too much stimulation by artificial calls can
change the behavior of these birds. This is why we are limiting the number of surveys to 3 per season per species. However, more frequent
calling will disrupt the owl's behavior and the effectiveness of the method itself. An owl who thinks its territory is being constantly "invaded" may
leave the area or spend too much time defending it and not enough time finding food or some other necessary behavior. It can also disrupt pair-
bonds and courtship. Try your best to spread out your surveys across the season.
- So, we also ask all of our participants to do their best to spread out their surveys. There's no hard line as to spreading them out, just leave at least
a few days in between each one. Obviously a limit of 1 survey a month per species is arbitrary and a few more will probably not harm the birds, but
there is a point where calling will affect the owls and we would like to err on the side of caution.
- MRGP researchers are on-hand to assist you and you should always feel free to contact us. We plan to conduct training sessions at the beginning
of the season, and we are certain that people with no experience can pick these methods up right away.
Thank you for your interest!
Some Details on our Methods
If you are interested in the details of our analysis, please see:
OCCUPANCY ESTIMATION AND MODELING by MacKenzie, Nichols, Royle, Pollock, Bailey, Hines
or
Occupancy/Presence website
Here is a brief explanation:
Many times, biologists are looking for a certain species in a number of locations. So they go out and look for it, in any number of ways appropriate to
catching or observing that species (e.g., cameras, traps, nets, tracks, or call surveys).
Usually they find the species in some sites, and don't find it in others. However, in those places that they are not found, the species could really be there
but the biologist failed to find it. This means that whatever method they used (traps, etc.) is imperfect and has a rate of failure.
Scientists can deal with imperfection and failure, if they can estimate what the rate of failure actually is. By doing repeated surveys in a set of locations,
you can estimate not only the places where the species definitely lives, but the places where the species probably lives even if you didn't find it. This
gives you a better estimate of the proportion of the total sites you looked that have the species (e.g., "60% of the places you looked are likely
occupied"). You can also estimate how effective your method is (called the detection probability), e.g., "you have a 80% chance of finding the species
using call surveys if it is actually there."
Once these two measurements are estimated, you can relate both to habitat or other variables. Did your detection rate go up (i.e., was the species
easier to find) when it was warm/at night/etc.? Were they more often found in the woods or in the city? Or, were they just easier to find in the city than in
the woods? In our study we are also interested to see if the two species are found together or do not overlap.
Repeated surveys at every location are necessary, even if you find the species right away. Without the repeated surveys, you could not estimate
detection probability.
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