(one tail)Northern
Saw-whet Owl Fall Migration Project
Hypothesis 1
Null: The number of females captured is less than or equal to the number of males captured.
Alternate: The number of females captured is more than the number of males.
Statistical test:
(one tail)
Hypothesis 2
Null: There is no difference in the proportion of age classes captured (HY=SY=ASY)
Alternate: There is a difference in the proportion of age classes captured
Statistical test:
Hypothesis 3
Null: There is no difference in the timing of migration for different age classes.
Alternate: There is a difference in the timing of migration by age class.
Statistical test: t test (normal) or Mann Whitney U (non normal). Must have equal variance for these tests. Other non parametric if equal variance not met.
Hypothesis 4
Null: There is no difference in the timing of migration from year to year.
Alternate: There is a difference in the timing of migration from year to year.
Statistical test: t test (normal) or Mann Whitney U (non normal). Must have equal variance for these tests. Other non parametric if equal variance assumption not met.
Other questions:
How long do owls stop over. Problem: Owls become net shy after first capture so detection probability decreases (by unknown amount) after each capture. We currently use 2 net runs with audio lures. Possible solutions: 1. Add passive net runs in study area and move them in a standardized way each night. 2. Find funding and radio tag captured owls.
If we radio tag owls, we could study habitat characteristics at roost sites in addition to stopover.
Project Protocol
(adapted from Kelly Williams-Sieg, Buzzard's Roost Station, Chillicothe, OH)
Liberty Station
Saw-whet
Owl Migration Project
Purpose:
The goals of the banding program are to:
Track timing of migration of age/sex groups
Study stopover pattern
Study molt and other aspects of biology in NSWOs
Use owls and owl banding to educate the public about conservation and wildlife issues
Train volunteers in bird banding techniques
Coordinator:
T. K. Tolford
P.O. Box 157
Liberty, IN 47353
513-200-5130
Methods:
The owl banding program will occur on a minimum of __5__ nights per week depending on weather conditions from approximately October 10 to December 10. Project leaders will set the start and finish dates each year as close to these targets as possible. Monitoring may begin earlier or end later based on information from other owlnet stations.
Trapping will begin one-half hour after sunset and continue for at least 4 hours. If interest and number of personnel warrant, banding may continue for more than 4 hours, but a net check should be completed at the end of the 4 hour period so that data can be standardized.
A minimum of two qualified people per night is recommended (one a licensed bander). If no one else is available, the station can be run with a single, licensed bander, but nets must be closed promptly if bird volume is too much for that person to handle safely and in a timely manner.
Trapping should not be conducted in rain, wet snow (light dry snow is acceptable), very strong winds, or in the presence of a predator. It is difficult to set absolute rules for wind interference as the effect depends on wind direction and placement of the nets, but generally winds about 15mph are too strong for this location. Safety of the birds is paramount, and the protocol should be abandoned temporarily if safety is compromised.
Two arrays of nets are set up (see site map in banding notebook). Net array “A” has five nets named 1, 2, 3, 4, 5. All nets are 12m, 60mm mesh. Net array “B” (6, 7, 8, 9) consists of four 60mm mesh nets.
Audio lures are placed in the center of each net run. A game caller should be placed at both net run “A” & “B”. Speakers from each run should face away from each other to maximize the area covered by the broadcast of the audio lure. Set volume at maximum and test audio lures. In the event that a game caller is not functioning.
Opening the station:
Arrive a half hour before sunset to allow time for set-up. Banding and broadcast equipment are stored in a storage area accessible to banders and designated volunteers. Place the game caller in the middle of net lane A with the speaker facing East. Place the speaker 2 ft from the ground in the brush behind the net and place the lid on the box after checking the tape volume (max). Place the other game caller (smaller speaker) in the middle of net run B on the tree shelf with the speakers facing North/South. The speaker volume should be turned to maximum volume.
Banding Protocol:
More than 3 birds are found at a single net check
there is a threat of precipitation
air temperature is below 20F
winds exceed 12mph
predators observed in the area
The audio lure should be turned off before birds are extracted. Restart the audio lures after the birds have been extracted. To avoid frightening owls in the vicinity, limit the number of people conducting net checks (1-3 people are sufficient).
Before removing the owl, note what net the owl is in and what pocket of the net it is hanging (pocket 1 is the bottom pocket, 4 is the top). Birds are to be placed in a separate lingerie bag and transported to the banding lab for immediate processing.
Processing owls
The
following is a list which shows every procedure to be conduced on each bird. A
more detailed version is available upon request, subject to consideration and
how the information will be used.
Band the owl
Flattened wing
Fat
Keel
Bill length
Bill depth
Exposed culmen
Foot pad
Feather pull
Face white-
Throat White-
Age
Molt Card
Weight
Retraps
Releasing the owls
Specific Problems
The bander in charge is responsible for all decisions to close down operations. Netting should stop if:
Wind is very strong (e.g. leaves being blown into nets almost as fast as they can be removed).
Nets are seriously damaged and it is impossible to quickly repair the damage.
Predators are present and pose a danger to the netted owls or if there is evidence of an owl being taken from the net. This would include a great horned owl or barred owl being flushed from the net area (not just calling in the distance). Close nets until suspected predators have left the area then initiate 15 minute net checks for the remainder of the evening.
Handling injured birds
Accidents happen, even at the most conscientious banding operation. In the event an owl appears to have suffered a sprain of the wings or legs that prevents it from flying or perching normally, place it in a small cardboard box with a piece of old towel on the bottom for padding, tightly close the box and place it in a warm (avoid overheating though), quiet location. Check the bird in an hour to see if it has improved enough for release. If not, contact the licensed rehabilitator listed below. Contact Kelly immediately if any injury occurs (home 775-6019, cell 804-2050)
If a bird has suffered any fracture, bleeding at any point or has suffered head trauma, call Tim Tolford and a rehabilitator immediately and place it in a small cardboard box with a piece of old towel on the bottom for padding, tightly close the box and place it in a warm (avoid overheating though), quiet location.
Melinda Simon, Licensed Wildlife Rehabilitator, Raptor, Inc.
phone # posted at banding station
Marilyn Arn
phone # posted at banding station
Jeff Hays, Raptor Inc.
phone # posted at banding station
Safety and security
Emergency #s: Union Co. Sheriff - 765-458-5194
Visitors
Liberty Station is privately owned and access is available upon request and during the project banding sessions. Visitors are permitted at the banding station but should be limited so as to not interfere with the banding operations nor disturb the neighbors. Organized groups (scouts, school students, conservation organizations, etc.) are to be encouraged but should contact Tim Tolford to make arrangements for the group to visit. Avoid bringing visitors on nights when a full crew is scheduled. All vehicles should be parked between the trees on the south (left) side of the driveway. If possible, please turn out headlights when entering the driveway as it is a private residence.