Author Archives: Nancy Drilling

Busy night at the owl-banding station

Last Saturday night, we finally got a full night of excellent weather at MSRW’s Point LaBarbe owl-banding station. Under high clouds, no significant precipitation and little wind, we caught a record number of owls. Sixty-one Northern Saw-whet Owls landed in our nets between 7:30 PM and 7:30 AM. Over 80% of these owls were young of the year (hatch-year) birds. Even though we have been catching a good number of already-banded owls this season, we had none for the night. In addition, we captured three Long-eared Owls – one hatch-year bird and two older owls.

We are getting close to the season records for number of owls caught at Point LaBarbe. The record is just under 550 saw-whets and we are at 540. So we are pretty confident that we will surpass this in the final two weeks of the banding season. The number of Long-eared Owls also is approaching a high number for this banding station. Will we surpass all records? Stay tuned for more of our record-setting season!

Owl-banding totals September 18th through October 24th:

Northern Saw-whet Owl: 540

Long-eared Owl: 8

Barred Owl: 2

Owl diversity in Michigan

At MSRW’s Point LaBarbe owl-banding station, we have been catching three species of owls this fall – Northern Saw-whet Owls (our target species), Long-eared Owls, and Barred Owls. In past years, the fall banding station has also caught Boreal Owls, which we would be delighted to catch this year. The checklist of Michigan birds lists 12 species that have been observed in the state. Can we hope to catch any of the other 8 species? The short answer is, probably not.

In the spring, MSRW operates an owl-banding station at Cheybogan State Park, which is at the north tip of the lower peninsula. Although very close to Pt. LaBarbe, the location and habitat is different enough to catch other owl species. Some nets at Cheybogan are set on the beach and occasionally catch Short-eared Owls, an open-country marsh and grassland bird. I saw a Short-eared Owl two nights ago on the road at Pt. LaBarbe but it was near the marsh and not near our nets which are set in gaps in the forest. So we are quite unlikely to catch a Short-eared Owl at our fall banding station because of the habitat where nets are located. Recently the Cheybogan spring banding has captured Eastern Screech-owls. This species is expanding its range northward in Michigan but has not been detected yet in the UP. So we probably are not going to catch one of these at Pt. LaBarbe. Great Horned Owls likely are around on both sides of the Straits in small numbers but they are not known to fly into nets at banding stations, even where they are common. Barn Owls are found in the southern part of the state and are also unlikely to make it into any of our nets on either side of the Straits.

The rest of the owl species on the Michigan list are very rare and/or occur in different seasons. The Upper Peninula hosts 3 species of winter owls – Snowy Owl, Great Gray Owl, and Northern Hawk Owl. Of these three, only the Snowy Owl occurs regularly, generally arriving in November or even later. The final species on the state list, the Burrowing Owl, is a vagrant from the Great Plains/western States with very few records in the state.

So we can reasonably expect just four species at our fall banding station. But that’s okay, we are capturing lots of owls, showing that at least some owl species migrate through the Straits in large numbers.

Owl-banding totals September 18th through October 22nd:

Northern Saw-whet Owl: 465

Long-eared Owl: 4

Barred Owl: 2

-Nancy Drilling, lead owl bander

400th Northern Saw-whet Owl

On the night of October 18th, we thought we had a big saw-whet night with 37 captures. But then last night, the 19th, we captured 43 saw-whets AND a Barred Owl, making it the second highest night of capture we’ve had so far this season. The calm weather and clear skies allowed many birds to move the last 2 nights, quickly bumping up our season total for saw-whets to 439. Unfortunately it looks like we’ll be rained out of banding for the next couple of nights, but hopefully we’ll get our 500th soon!

Our 400th Northern Saw-whet Owl capture of the season, on the night of October 19th, 2020. Photo by Kandace Glanville.

Owl banding totals September 18th through October 20th:

Northern Saw-whet Owl: 439

Long-eared Owl: 3

Barred Owl: 2

-Kandace Glanville, assistant owl bander

A primer to ageing owls

In addition to putting a band on each owl we catch at MSRW’s owl-banding station on Point LaBarbe, we take a variety of measurements and we try to determine the age and sex of each individual. Determining the age of a bird helps us understand population dynamics of a bird population. For example, if we catch a high number of young of the year (aka hatch-year birds) in the fall, this tells us that reproduction was good last summer.

So you may ask, how does one age an owl? We take advantage of the fact that owls have an incomplete molt, which means that during their once-a-year flight feather molt, they only shed some of their flight feathers while retaining others for up to three years. Thus, for example, a two year old owl has both new feathers and one-year-old feathers in its wing. A three year old owl has new feathers, one-year-old feathers and two-year-old feathers in its wing. The only time an owl has a complete set of new feathers is during its hatch year, when it has to grow an entire set of feathers after hatching.

The different feather ages are especially easy to see in Northern Saw-whet Owls. New flight feathers contain a chemical called porphyrin which fluoresces bright pink when we shine a UV light on the wing.

UV light set-up to determine age of saw-whet owl flight feathers

Here is a photo of of the wing of a hatch-year bird with a full complement of new feathers. All of the new feathers flouresce bright pink.

Molt pattern of a hatch-year saw-whet owl. Photo by Kevin Perozeni.

This chemical breaks down as the feather ages and thus, older feathers do not fluoresce. In the following photo, a second-year bird has two age classes of feathers – the bright pink new outer and inner feathers which it has recently replaced and the pale one-year-old feathers in the middle. This is the classic molt pattern of a second-year saw-whet. When we see this pattern, we can be confident in calling a bird two years old.

Molt pattern of a second-year saw-whet owl. Photo by Kevin Perozeni.

After the second year, there is no regular pattern of molt and any feathers could be replaced at anytime. Thus whenever we see an irregular molt pattern, we can only say that the owl is older than two years. For example, in the following individual, the outer primaries and a group of feathers in the middle have been newly replaced.

Example of a molt pattern of an after-second-year saw-whet owl. Photo by Dawn Garcia

We can also use the UV light to examine feather age in other owl species, but more typically, we look at the shape and extent of barring on particular feathers. For example, the barring on the central tail feather of the Barred Owl we caught earlier this fall tells us that this bird was more than two years old.

Tail of a Barred Owl showing barring pattern of an older bird. Photo by Kandace Glanville

Owl-banding totals September 18th through October 15th:

Northern Saw-whet Owl: 359

Long-eared Owl: 3

Barred Owl: 1

-Nancy Drilling, lead owl bander

Banding Set-up & Our 300th Northern Saw-whet Owl!

Point LaBarbe is an important geographic location for southern migration in the fall. It’s the very southern tip of Michigan’s Upper Peninsula, and birds funnel through here on their way south, before crossing the Straits. Why risk flying over large bodies of water when you can migrate over land?

One of our audio lures. Photo by Nancy Drilling.

As the owls are migrating south at night, they’re listening and looking around for maybe a place to roost for the day to rest and finish their migration the following night. Or they’re looking for a snack (probably a small rodent) to give them the energy to keep moving. Most saw-whet banding operations use audio lures to draw in these birds as they pass through on migration. The audio lures play their “toot” calls on repeat. Whether the saw whets are drawn down to the audio from some sort of breeding aspect, or because they think the calling saw whet knows something about that area being good habitat, it’s not really known. Either way, they end up in our nets! We process them as quickly as we can, and release them to continue on their Autumn journey south.

Kandace setting up the nets on the East side of the point. Photo by Kathy Bricker.

We have 3 nets set in a triangle, with an audio lure in the middle. Our other net arrangement is approximately a mile away on the other side of Point LaBarbe, and it consists of 7 nets, in a sort of T-shape with the audio lure at the center. We also have 2 “passive” nets without an audio lure set up in the middle of the point, between the two audio arrangements, for 12 nets total. We extract the owls and take them back to our banding trailer on the west side of the point, where we quickly band and process them before releasing.

In the last few days we’ve dealt with some unfavorable weather for banding, including rain and lots of wind, which caused us to close nets early or not open them at all for the night. But we still managed to catch our 300th Northern Saw-whet Owl of the season, on our one night of good weather!

Our 300th Northern Saw-whet Owl of the season! Photo by Kandace Glanville.

Species totals September 18th through October 12th:

Northern Saw-whet Owl: 311

Long-eared Owl: 2

Barred Owl: 1

Eastern Whip-poor-will: 1

-Kandace Glanville, assistant owl bander

Weather, weather and more weather!

Not only does weather affect bird activities, including migration, it also affects field biologists’ activities. At the MSRW owl-banding station on Point Labarbe, we have not been able to open nets for three of the past five nights because of weather. One night was canceled because of rain. Obviously we should not try to catch owls in the rain and owls probably aren’t migrating in such weather anyways. Two nights, including last night, were canceled because of high winds. Owls may be on the move in such conditions but winds blow the netting around, potentially injuring a netted bird. We generally have a cutoff of ~15 mph winds but it depends on wind direction and the placement of our nets. Sometimes nets are protected from winds by the surrounding trees and we can try to catch owls. If not protected enough, we don’t open nets or close open nets when they are blowing around too much. Then we go to sleep, something in short supply during owl-banding season!

On the other hand, Ben and Calvin, MSRW’s waterbird and hawk counters respectively, love wind because they generally count more diurnal raptors on windy days. When it rains, they still have to count so they pull out the umbrellas (or sit in their cars). Check out their results in their blogs on this site! Because they work during the day, they can sleep at night like normal people and aren’t sleep-deprived, except when they help us at the owl-banding station.

Owl-banding totals September 18th through October 8th:

Northern Saw-whet Owl: 292

Long-eared Owl: 2

Barred Owl: 1

-Nancy Drilling, lead owl-bander

Why we band owls

Over the past two nights, we have captured 26 Northern Saw-whet Owls (‘saw-whets’) at the Point Labarbe owl-banding station, for a season total to date of 247 saw-whets. Thirteen of the 247 owls were already banded when we captured them. Because every band has a unique number, we are able to find out where and when each owl was initially banded. Two of these were banded by MSRW owl-banders in previous years – one at Point Labarbe in Fall 2019 and one at Cheboygan State Park in April 2018. The other 11 birds were banded by someone else, known as ‘foreign recaptures’ or ‘recoveries’. At the moment, we only have information on one of these – an owl originally banded at Stevens Point, WI in November 2019. Based on band numbers, many of the rest of the foreign recaptures likely are from Whitefish Point, about 80 miles northwest of Point Labarbe.

Details of a saw-whet band showing unique number. Photo by Rheanna Fraser

All of this leads to a discussion of why we are going to such great lengths to capture and band Northern Saw-whet Owls, our target species. Broadly speaking, we are seeking to shed light on saw-whet migration – patterns and timing – through the Mackinac Straits, Michigan, and North America. Before MSRW co-founder Ed Pike began capturing owls around the Mackinac Straits in the early 2000’s, saw-whets were thought to be a rare species in the area. His data show that a significant number of owls migrate through the straits (E. Pike. 2018. Fall Owl Banding at Point La Barbe, Mackinac Co., Michigan. Michigan Birds and Natural History 25(3): 156-162). Ed has shown that some owls are migrating straight south across the Upper Peninsula, some continue migrating south into Indiana, and some owls remain for months in eastern Upper Peninsula. Ed has also shown that some owls appear to use the same migration route in multiple years while other individuals use different routes during fall and spring migration. Not only does this data help us understand migration in Michigan, the MSRW banding stations are part of Project Owlnet, a continent-wide network of owl-banding stations.

Banding not only elucidates migration routes, but also contributes to our knowledge of owl populations. Saw-whet populations cycle through boom and bust years. This fall, we are capturing a record number of owls, almost all of which are hatch-year females, suggesting we are at the high point of their population cycle. In addition to all of this, data that we collect on each owl (measurements, age, sex) are valuable in and of itself, even if the owl is never recaptured again.

Species totals September 18th through October 4th (Sunday night):

Northern Saw-whet Owl: 247

Long-eared Owl: 2

Barred Owl: 1

Owl-banding update: Every night is different

Thursday and Friday nights provided a lot of excitement at the owl-banding station at Point Labarbe but despite similar weather conditions, they couldn’t have been more different. Thursday night, under bright cloudy skies, a northwest breeze and chilly temperatures, Northern Saw-whet Owls came through in flocks, at a clip of 10 – 15 owls netted per hour. We ended up with 58 saw-whets for the night, despite having to close some nets for a few hours. This is not quite a one-night capture record, but its close!

Weather on Friday night was similar and we thought we would have another block-buster capture night. However, the saw-whets did not get the message and we ‘just’ caught 20 saw-whets, with the last capture at 2:30 AM. Normally, 20 owls in a night would be noteworthy but this is not a normal year! The highlight of the night came around midnight, when a Barred Owl went into our nets. Based on her size, it likely was a female. A beautiful bird and the first that either Kandace or I had banded.

Bander Kandace Glanville with our first Barred Owl capture of the season. Photo by Nancy Drilling

There are four owl species that could be caught at the Pt. Labarbe fall station: saw-whets, Long-eared Owl, Barred Owl, and Boreal Owl. We have now caught at least one individual of three species. The fourth, Boreal Owl, is the rarest, especially in fall, but we are rooting for at least one to find our nets.

Species totals through October 2nd (Friday night):

Northern Saw-whet Owl: 221

Long-eared Owl: 2

Barred Owl: 1

Eastern Whip-poor-will: 1

Nancy Drilling

Net Checks

Bird banding can be very fast-paced on a busy day, but oftentimes it can also be very slow while you’re waiting for birds to be caught in nets or traps. So what do banders do while they’re waiting for birds to band?

Most banding operations that use mist nets have something called “net checks,” which are often regularly timed rounds when they go check to see if their nets caught birds, which they would then extract and band. These net checks are usually every 30-60 minutes or so, depending on the type of banding you’re doing, what the weather is like that day (or night!), and other miscellaneous factors that might cause you to check the nets more often (predator in the area, lots of birds moving through, etc.). You want to leave the nets alone long enough that the birds can move around naturally and freely so that you hopefully catch some. Though you don’t want to leave the nets alone too long, with fear of birds becoming too entangled, warm, cold, or exposed to predation, all of which could possibly lead to injury.

Our net checks for owls are between every 30-60 minutes, depending on weather and owl movements for each night. Our nets are in two separate locations, just about a mile apart, so Nancy and I split up for each net check. Usually each night we switch which side we do, so that we don’t become too bored or frustrated with a set of nets! Sometimes we might catch 5-10 owls per round, in which case we’re processing them as quickly as we can so that we get out to the nets again in time for the next round. If we come back from a net check round with only a bird or two, then we have plenty of time until we have to make our rounds again. We often talk and hang out between net checks, or we read, do Sudoku and other such puzzles, eat lots of snacks, or most recently, we completed a puzzle! We’ll see what else we come up with to pass the time as the season goes on. Though hopefully we’ll stay busy enough with a lot of owls!

Even when we’re not banding owls, we’re thinking about owls… a puzzle was a good way to pass the time between net checks!

Though we were rained out the previous two nights, we stayed plenty busy with lots of saw-whets, and a surprise Eastern Whip-poor-will that was in one of our nets as we were just getting ready to close them around 7:00am. Hopefully we’ll have some more good weather and owl movements for the days to come. This brings us up to 143 saw-whets captured in 10 nights of banding! Here’s our banding update from the last couple days:

29th: rained out

30th: 33 saw-whets, and an Eastern Whip-poor-will

A surprise Eastern Whip-poor-will that we extracted from a net this morning at around 7:00am.

-Kandace Glanville, Assistant Owl Bander

Owl banding season is off to a fast start!

The owl-banding season at Point Labarbe typically runs from September 20th to November 10th, which should cover the entire migration period of Northern Saw-whet Owls (“saw-whets”). Usually the season starts slowly and the first few nights, banders sit around struggling to stay awake and hoping for a bird or two. Not so this year! Ed Pike and Shannon Dolan did a warm-up banding session on the 19th and caught an amazing 10 saw-whets. And they just keep coming – 110 saw-whets in 8 nights.

Long-eared Owl. Captured Sept. 23, 2020 at MSRW’s Point Labarbe owl banding station. Photo by Kandace Glanville

On September 23rd, we were delighted to catch the first Long-eared Owl of the season (see photos). This is quite early for this species. In owls, males tend to be smaller than females but there is broad overlap in the sizes of males and females. This bird was intermediate in size so we could not determine its sex. By examining details of the barring on some of its feathers, we determined that this bird was at least three years old.

Underwing of Long-eared Owl. Photo by Kandace Glanville

We keep the nets open, weather permitting, from dusk to first light, currently for about 11 hours. In the first few nights of the season, rain has shortened our efforts on two nights. September owl captures so far:

19th: 10 saw-whets

20th: 5 saw-whets

21st: 12 saw-whets

22nd: 22 saw-whets

23rd: 18 saw-whets, 1 Long-eared Owl

24th: 5 saw-whets (short night)

25th: 8 saw-whets

26th: 5 saw-whets (short night)

27th: 25 saw-whets

28th: rained out

The Point Labarbe fall banding station usually captures 300 – 400 saw-whets in a season. At this pace, we will capture more than this in Fall 2020. Saw-whet populations fluctuate widely among years, with peak abundance occurring every four years. This may be one of those peak years. Or, maybe it is a ‘normal’ year in terms of numbers but the migration has shifted earlier. Only time will tell! Stay tuned …..