WPBO Owls Fall 2010

Thursday, April 22, 2010

Barred Owl

Frequent high winds have been making it difficult for us to get in a full night recently. When we have been able to open it has been relatively slow, but fairly steady. In the last four nights we have banded 27 Saw-whets, 5 Long-eareds, and 2 Barreds. There have been no Boreals since the 11th, and no Great Grays since the 3rd. However, this time of the season is typically very productive and we're hoping some south winds will pick things up again. Spring Fling is this weekend and we're particularly excited about this year's keynote speaker. Norm Smith is the director of Massachusetts Audubon's Blue Hills Trailside Museum and the Norman Smith Environmental Education Center. Among other projects, Norm has been conducting research on wintering Snowy Owls in Massachusetts for several decades. Nova and I have had the opportunity to see his program which focuses on his Snowy research and we absolutely love it. It is a great mix of entertainment and information, we can't wait to see it again.

Monday, April 12, 2010

Tonight's Northern Lights

Last Week's Snow

Long-eared Owl

After being shut down for a few nights due to weather, including about 6 inches of snow, we've had a few nights of decent weather. The owls have remained relatively slow, but there has been some activity. In the last three nights we have banded 14 Saw-whets, 2 Boreals, and 2 Long-eareds. We also recaptured a Barred that we banded last spring and another one that was banded in Michigan in the spring of 2008. Three of the four Barreds that we have now caught this season were previously banded. It has been a while since we have seen the Northern Lights, but we were treated to some nice ones tonight. Typically the lighthouse would have made the top photo impossible, but it is currently not operating. In other news, there is now another place to get breakfast in Paradise. In addition to the Berry Patch, The Yukon is now serving breakfast. As it says on their banner "Over 70 Served", make it 72. Nice to fill our stomachs after a long night.

Nova ready for a Yukon breakfast

after a night of banding.

Chris & Nova

Tuesday, April 6, 2010

Great Gray Owls

Great Gray Owl wing

April has gotten off to a decent start, but given the favorable weather conditions we are a bit surprised that there hasn't been more activity. April 1-4 results; 38 Northern Saw-whets, 4 Boreals, 13 Long-eareds, and 1 Barred. As we mentioned in our last post, 2 Great Gray were caught on the 31st, one of which was previously banded. The banded owl was originally banded as an adult in Alcona, Ontario on January 7, 2005. This means it was born no later than 2003, and will therefore turn at least 7 years old sometime within the next few months. According to the Banding Lab's data this is the third oldest record for a wild Great Gray Owl. This is the left bird in the top photo and it weighed about 20% more than the other Great Gray. In the bottom photo you can see how broad and square tipped a Great Gray's wings are. You can also see the old faded feathers which were not replaced during the most recent molt.

Chris & Nova

Thursday, April 1, 2010

A Productive March

One of last summer's adopted juvenile Saw-whets!.

As March comes to an end we're very happy with the season's results so far. Already this season 225 Northern Saw-whet, 4 Boreal, 16 Long-eared, and 4 Great Gray Owls have been banded. Additionally, 17 previously banded owls have also been captured; 15 Saw-whets, one Barred, and one Great Gray. The banded Great Gray was caught last night and we are able to get some basic information back instantly from the Banding Lab's online database. This Great Gray was originally banded in Ontario in January of 2005, we'll receive full details after they receive our information. Also of interest was a Northern Flicker feather stuck to the undertail coverts of a Saw-whet (photo below). We've also been thrilled with the recapture of 5 Saw-whets that we banded as juveniles during our summer research; 1 from 2006, 2 from 2007, and 2 from 2009. Among these was the one in the above photo which was adopted last summer by John McAree. John is a regular visitor to the Point and he collected the most pledges for last year's WPBO Staff Birdathon. Whenever we recapture one of our owls we check our records in hopes that it was adopted through our Sponsor-A-Raptor Program. It was great to see that it was one of the adopted birds John received in return for his generous pledge. Without the money raised by the birdathon the summer research would not be possible. Thanks John!

Flicker feather on a Saw-whet.

Chris & Nova

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.

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.