WPBO Owls Fall 2010: July 2010

Monday, July 26, 2010

Molting juvenile Northern Saw-whet Owl

The banding has been going well. The weather caused us to close early a couple nights and wind shut us down completely on Saturday night. The system finally blew out of here and 30 juvenile & 1 adult Saw-whet were banded last night. We also saw a Long-eared in the net lanes, but it was not caught. So far this season 204 juvenile & 34 adult Saw-whets, and 2 Long-eareds have been banded. After banding just 60 juveniles in 2008 and 189 last summer it's nice to see the breeding success rebounding more this summer.

The summer is interesting not only due to the unique nature of our summer owl research, we are the only site where movements of juvenile Saw-whets have been documented, but also because of the visitors. During the spring & fall seasons we obviously get a lot of birders. During the summer we get many more families & visitors who are not necessarily birders. It is very rewarding to us personally to be able to share these beautiful birds with these visitors. In return many of these visitors have been supporting WPBO through our adopt-an-owl program. In the 14 seasons I have spent here as an owl bander this is by far the most on site support we have recieved through this program. Nova & I want to thank our fellow staff Jason, Joanne, Betty, Lynn & Libby for promoting the owl research. We would obviously also like to thank all of you who have contributed to make this research possible.

Chris & Nova

Sunday, July 18, 2010

Long-eared Owl

If you happened to read our last post we'd just like to say we are not meteorologist, we're simply among the idiots that rely on them. After the very productive night on the 15th we were geared up for another good night on the 16th. The weather predictions were unfortunately not accurate and with high winds limiting our efforts just 2 adult Saw-whets were banded before we had to shut down. Conditions were decent last night and 19 juvenile Saw-whets and the season's second Long-eared were banded. While we band many more Long-eareds during the spring season, there are a couple things that we see in the summer that we have never seen in the spring. During the summer research we have caught several Long-eareds that were so young that they still had retained natal down. As chicks they are covered with gray downy feathers, their natal down. They then grow in body feathers that are indistinguishable from adult feathers. It is truly amazing to see these patches of gray downy feathers on a full sized Long-eared and realize that just a few months ago these beautiful birds were eggs. Adults we band in the summer are often actively molting their flight feathers. The bird in the above photo has just begun this molt. The uneven trailing edge of the wing is due to that fact that it has just dropped its innermost primaries. These dropped feathers had just begun growing back in and were pin feathers similar those on the Saw-whet pictured in our post from the 10th.

Chris & Nova

Friday, July 16, 2010

The Summer Research's Biggest Night!

Saw-whets, adult left & juvenile right

molting juvenile Saw-whet

After experiencing a particularly early owl migration this spring, we are now seeing an early movement of juvenile Saw-whets this summer. We banded 4 adult and 50 juvenile Saw-whets last night. In just its 5th season the summer research is still relatively new, but this is both the highest nightly total and the most juveniles banded in a night. We will not be surprised if this turns out to be the season's peak night. That being said, we are still approaching what was the most productive period during the first 3 full summer seasons and last night certainly got us into full swing. In addition to experiencing early movements we are also seeing birds at advanced stages of their post-juvenile molt compared to previous seasons. The lower photo shows a juvenile molting out of its juvenal plumage. You can see the white adult feathers along the earflaps and in the facial disk. The weather conditions look good for tonight, hopefully it will be another productive one.

Chris & Nova

Saturday, July 10, 2010

Long-eared Owl

Saw-whet pin feathers

Black-billed Cuckoo

After a nice start to the season on the 1st, bad weather kept us from opening nets on the 2nd, 3rd, 4th & 5th. We were then only able to get a couple hours in on the 6th and 7th. On the 6th we caught no owls, but did catch a Black-billed Cuckoo. On the 7th we caught one adult Saw-whet. Even for Whitefish Point this was a long spell of bad weather. The weather finally broke on the 8th and we banded 9 adult and 9 juvenile Saw-whets. One of the adults was actively molting its flight feathers, the middle photo above shows a couple of its primary flight feathers just beginning to grow back in. Last night we banded 12 juveniles & 1 adult Saw-whet and the season's first Long-eared. This is the earliest arrival date for Long-eared Owl during the summer research. The Long-eared was one of this year's young and still had some retained natal down. While it was the sighting of 3 Long-eareds and a juvenile Saw-whet on July 21, 2006 that led to the summer project, this is the first Long-eared to be banded in July, and the first July record since 2006.

Chris & Nova

Friday, July 2, 2010

The Summer Season Begins!

Junenile Northern Saw-whet Owl

We really need to start off thanking everyone who pledged to this year's WPBO staff bird-a-thon. The amount of support you have provided has increased in each of the four years that we have run this event. This year $9,700 was raised, enough to fully fund this summer's research! The very simple truth is that without your pledges to the bird-a-thon we would not be able to continue this research. This study remains unique and is just another example of why Whitefish Point is such an amazing site. Thank you so much for your support.

Given that Saw-whets moved early this spring we had concerns that breeding may have begun early and juveniles might therefore begin moving paricularly early this year. We ran the nets one night last week to see what was happening. Fourteen adults were banded, but no juveniles were caught. We opened again on June 30 and banded nine more adults and caught 3 banded Saw-whets, including two of our birds from mid April. Last night was the official start of the season and we banded 5 adults and 4 juveniles. A very nice start to the season.

We'd like to thank the 30 or so folks who attended the owl program this evening. Special thanks to those who adopted 4 Saw-whets tonight. One was adopted by a local couple and 3 were adopted by a father and 2 daughters from down state. This family made a special 500 mile one day round trip to see the owls. Well our brains are suffering from switching over to a nocturnal schedule again. Nova is in bed and my eyes are closing as I'm trying to write this post, hopefully it is coherent.

Chris & Nova

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.