WPBO Owls Fall 2010

Wednesday, March 24, 2010

Long-eared Owl

Things have levelled out a bit, but have remained steady since our last post. After our big night of 73 owls on the 17th, we banded 34 Saw-whets and 1 Long-eared on the 18th. High winds caused us to keep the nets closed on the 19th, but the weather has been fairly cooperative the last 4 nights. Over these four nights 36 Saw-whets, 3 Long-eareds, and 2 Great Grays have been banded. A Great Gray was also seen on the night of the 22nd, on which night none were banded. Given that the previous arrival date for Great Grays was April 2nd, the fact that at least 3 have already been present at the Point this spring is very unexpected.

The banding season to date:

173 Saw-whets banded & 8 recaptured, 3 Boreals, 5 Long-eareds, 1 recaptured Barred, and 3 Great Grays.

Thursday, March 18, 2010

1st Great Gray & Long-eared of the spring

Great Gray Owl

Well this season has really started off with a bang. Along with the first Great Gray and Long-eared Owls of the season we banded 69 more Saw-whets and 2 more Boreals last night. We also recaptured a Saw-whet we banded in the spring of 2007, and one of our juveniles from the summer of 2007. While we appreciate every owl we get to see, there is truly something special about recapturing Saw-whets we banded as juveniles. These recaptures are also extremely useful to us as we get to see molt patterns on birds that we indisputably know the age of. The weather looks good again for tonight, hopefully it will be another productive one.

Chris & Nova

Wednesday, March 17, 2010

Spring 2010 is under way!

Boreal Owl

Northern Saw-whet Owl

Nova & I are very happy to be back at the Point after spending another winter at Laguna Atascosa National Wildlife Refuge in Texas. While we're struggling with changing over to a nocturnal schedule and the long nights, there is very little snow in the woods this year which makes things much easier. The season has gotten off to a productive start . After a half night on the 14th and 2 full nights we have banded 34 Saw-whets and one Boreal. The Boreal was banded on the 15th representing a new early spring arrival date for WPBO. There have also been four previously banded Saw-whets and 1 banded Barred captured. Three of the Saw-whets and the Barred were originally banded here. Two of the recaptured Saw-whets were originally banded as juveniles in the summer. One of these was banded in July 2006 on just the 2nd night we ever ran the summer project (photo above), the other was banded last summer. The other recaptured Saw-whet was originally banded on May 29, 2009, the second to last night of the season as opposed to the second night of the season this year. A very nice start to the season.

Thursday, October 29, 2009

A Few More Birds

We are not banding tonight due to windy and rainy weather. Two nights ago on the 27th we banded 5 Northern Saw-whets and had a NSWO foreign encounter. If you remember from earlier blogs an encounter is a bird that is already banded. A foreign encounter is a bird banded from a different location. The four other encounters we have had this season were not foreign, all banded here at Whitefish Point. We don't know where the foreign encounter was banded. It will be interesting to find out where it was originally banded.

Only a couple more nights of banding. The weather forecast isn't looking good. Maybe Saturday night if it isn't too windy.

Totals: 3 BDOW, 2 BOOW, 1 LEOW, 123 NSWO

Monday, October 26, 2009

Quiet Times

Not much to report on. I just felt like I should update the blog. We have not banded a new bird since the 17th. This can be mainly attributed to crummy weather. We have been having more rain and wind. Oh well ,what can you do?

A visitor to the point today saw a Long-eared Owl roosting. We were hoping it would stick around and get caught in our nets. Unfortunately, we had to close the nets due to intermittent rain and strong winds.

I was looking through my pictures and found this one of a Northern Saw-whet about to take off from Tim's arm. Just look at that little owl, how could you not love them?!

Our last night of banding is on Halloween. I hope we get to see a few more owls before the 31st. We'll see.

Totals: 2 BOOW, 3BDOW, 1 LEOW, 118 NSWO

Our New Summer Owl Study

During the summer of 2006 WPBO conducted an exploratory owl banding research project at the Point. Our project ran 3 weeks, and our efforts resulted in the capture of 208 owls; 206 Northern Saw-whet Owls (NSWO) and 2 Long-eared Owls. Of the 206 NSWO captured, 200 were juvenile birds. While the spring and fall migrations of NSWO have become increasingly well studied across the continent, these results represent the first documentation of a significant concentration of juvenile NSWO during the post-breeding period.

Thanks in large part to generous donations made by two individuals and pledges to the spring staff birdathon, we have been able to continue and expand this study during the summer of 2007. We began on July 1st, and as of August 10th we have banded 542 owls; 539 NSWO and 3 Long-eared Owls. As in 2006, the majority of the NSWO we have banded this summer have been juveniles.

In addition to the regular data we collect on all owls, we are visually accessing fat stores and muscle mass on all of the juveniles. Among North American owls only NSWO and Boreal Owls have a juvenile plumage that is significantly different from adult plumage. The juveniles begin actively molting out of their juvenile plumage and into adult plumage during our study period. Detailed descriptions of the molt progression on each juvenile have been collected.

Owl banding Spring 2007

Several changes were made to the spring owl banding protocol in 2007. These changes were made in an effort to increase our captures, thereby increasing our data base and our knowledge of the owl migration at Whitefish Point. Owl banding data collected by WPBO during previous springs clearly demonstrated that the Saw-whet migration at Whitefish Point was already at its peak during the 1st week of April. Therefore, the start date of the spring owl research was moved up from the previous start date of April 1st to March 15th. Audiolure was also introduced to the spring owl research for the first time. Audiolure is simply the practice of broadcasting a recording of an owl's call to lure them into the research area. This is a technique implemented at every other owl migration banding site that we know of, and has been used during the fall season at Whitefish Point since the fall study began in 1993. It has been documented that this practice increases Saw-whet captures 5-10 fold.
This spring the calls of Northern Saw-whet and Boreal Owls were broadcast. As the data from previous seasons suggested would be the case, Boreals were at the bottom of their irruptive cycle and none were captured. We fully expect that Boreal Owl captures during the next irruption will increase significantly due to the use of audiolure. As for Saw-whets, the changes proved a huge success after just one season. We banded nearly 280 Saw-whets during March alone; the previous high for an entire spring season was 122. Our total captures for all owl species in March was 318, these results are also higher than the total captures of any previous spring season. The chart below demonstrates the effectiveness of the changes implemented in the spring of 2007.

General Information

Whitefish Point Bird Observatory (WPBO) conducts long-term owl migration studies in both spring and fall. WPBO began its oversight of the spring owl research at Whitefish Point (WP) in 1988, and began the fall study in 1993. A summer study was developed during the summer of 2006 when a dispersal of juvenile Northern Saw-whet Owls was discovered within the study area. These WPBO research projects have resulted in the banding of over 7,000 owls of eight species; Great Horned, Northern Hawk, Barred, Great Gray, Long-eared, Short-eared, Boreal, and Northern Saw-whet. This reasearch has established WP as one of the most diverse owl migration sites on the continent.

* Study periods:
Spring: March 15-May 31
Summer: currently July 1-August 31
Fall: September 15- October 31

**During the study periods nets are opened nightly, weather permitting , 1/2 hour after sunset and closed 1/2 hour before sunrise. Nets are not opened during periods of rain or high winds.

FAQs

Why do we band owls?
The owl banding project is the most effective way we have to monitor the number of owls migrating through Whitefish Point. For example, without the owl banding project just 3 Saw-whet Owls would have be documented in the spring of 2007. Through the owl banding project, 750 Saw-whets were banded and 32 that were already banded were caught. Without specific efforts to document the owl migration at Whitefish Point it would go virtually undetected. For more information on bird banding visit the Bird Banding Lab's website, which can be linked out of the WPBO website.

How do we catch and handle the owls?
All of the owls in our studies are captured in mist nets that are made specifically for bird banding. The mist nets we use are 12 meters long andabout 10 feet high. Due to the size difference between species that we catch two different mesh sizes are used. The nets are placed in openings among the trees at Whitefish Point. To help attract the owls into the netlanes audiolure is used. Audiolure is simply the broadcast of an owls call.In spring and fall both Saw-whet and Boreal Owl calls are broadcast, only saw-whet calls are broadcast in the summer. We do not wear gloves while getting extracting owls from the nets or during the banding and measuring proccess. Like many other things, these procedures are more difficult when wearing gloves. Extractions in particular are already difficult and would be virtually impossible while wearing heavy gloves. Yes, we do occasionally get bit or have the birds get us with their talons, and yes it does hurt. To band and weigh the owls they are placed in cans. This is the common practice when banding birds of prey and actually serves to calm the birds down.

What data do we collect?
Each owl is fitted with an individually numbered U.S. Geological Survey band. These bands are issued to federally licensed bird banders by the Bird Banding Lab in Maryland. The main measurments we collect are weight, tail and wing chord length. If the bird has flight feather molt, the molt pattern is recorded. These measurements and the molt patterns help us determine the age and sex of many of the owls that are captured. The data, including the band number is then submitted to the Bird Banding Lab for inclusion in their database.