birdbling

Snow Goose Festival Outing 2012 - Owl Success!

2012-02-10T14:26:00.000-08:00

Every season for the Snow Goose Festival we offer our Northern Saw-whet Owl banding and survey. It is always a sell out and this year was no different. The late January date (26) also allows us to see if we continue to have wintering saw-whets on the Reserve. We always start off with an owl prowl to survey the other species in the area. This year we had the resident pair of Great Horned Owls, putting on a nice vocal show of dueting.

As in most raptors the female is bigger than the male, but in the owls, the female has a higher pitched voice, making a nice auditory duet of high (female) and low (male) responses. I love this picture from the web showing the size difference, although these birds are much lighter in color than the Reserve pair. We also had a Western Screech Owl calling in the fog, very close over our heads with only nearby trees visible - very dramatic! Saw-whets were calling vocalizations that we describe as banshee wails, chitters and squirrel chirps. It was a very active night for our participants ears!

Our most exciting moment though was on the very last net run of the night - when two (seen in this pic held by me and Raina) Saw-whet owls flew into the nets, one right in front of our guests. We were all very awed as usual by the beauty of the little predators, and ended the night knowing that indeed, two new owls (previously unbanded) were wintering on the Reserve. Of course it is unknown to us if these owls have been here since fall migration and avoided the nets, or came in later, after our migration station had closed for the season. Another mystery!

Thank you Steve and Raina King and Nancy Nelson for helping with another successful owl adventure!

OWL FANS!

2011-12-29T18:46:00.000-08:00

Our banding crew loves to bring visitors to our owl station, particularly children. They are so excited to be out in the night, to walk through the woods with a headlamp and to meet their neighbors of the night- the owls! When we talk about the ecological value of owls, they get it. Here are two of our happy young visitors,

an owl they met,

and examples of thank yous that we receive from very happy kids. I love their excitement about the night, and you can read that we do sometimes provide treats - in this case jelly belly beans which made one guest, Maile, very happy!

I love this drawing of us checking the nets with our headlamps and finding an owl (in blue) in the nets-always a great surprise!

Our Foreign Recovery - A Montana Girl!

2011-12-10T11:02:00.000-08:00

My previous post tells about Lola, a foreign recovery of unknown origin. It turns out after we queried our way through the western states, we found that she was originally banded in the Bitterroot Valley in western Montana (!) by researchers at the Owl Research Institute. Her original band date was September 28, 2011,where she weighed in at 93.0 grams. On November 2, 2011 at our banding site OWL2, she was 91 grams. This two year old lady did some traveling; approximately 600 miles in 35 days. Check out this map of her approximate original banding location to our site.

Wouldn't it be great to know where she stopped in between, and where she was hatched-she could be Canadian! We still are not sure if she was banded during a migration monitoring effort (but likely since it was late September) or for some other research project. More to come - stay tuned!!!

End of Season Results are IN!!!

2011-12-06T06:46:00.000-08:00

While we are always excited about beginning our migration monitoring season, we are also excited to complete the season, to see what the population of saw-whets looked like this year and how it compares to others. This season, our 7th year of monitoring, we had another outstanding fall, banding 90 saw-whets! We also had our very first ever foreign recovery. This means that some other banding station banded the bird, and she was recaptured at our station. This picture of our foreign recovery we named Lola, was taken by saw-whet owl researcher Julie Shaw, after we fit her with a radio transmitter to follow her movements. Although this photo makes Lola appear angry, the elongated, slimming posture is also a cryptic behavior (although she might have been a little peeved that she was found during the day on her roost!).

While currently we don't know where she was originally banded, we should early 2012 after all banding data is submitted to the Bird Banding Laboratory.

But back to our usual excitement! During the fall 2011 season we captured and banded 90 owls. An examination of the population is dominated by adults (51, those hatched in 2010 or earlier) with only 39 hatch year birds (those hatched in 2011). This ratio of adult to young birds indicates good survivabilty of adult owls, and perhaps a lower productivity or a lower survival of young birds. Next posting I will compare these numbers to 2010 owls.

OWLOWEEN - A night of Ghosts and Owls

2011-10-30T06:58:00.000-07:00

One of our most fun and popular evenings during the owl season is Altacal's OWLOWEEN field trip where we play tricks, provide treats and teach people about our Northern Saw-whet Owl migration monitoring study. Here's how it went last night. After Steve King picked up 10 guests to bring to the Big Chico Creek Ecological Reserve - our banding site OWL2, we tried to conjure up some of our resident owls, great horned, western screech, pygmy and even gave a few attempts for barn, barred and spotted. Our witchcraft was limited we had responses from two pygmy owls and later heard a chirping Northern saw-whet owl. We walked through the twilight to the Lucas cemetery, where I told the story of the raven-haired beauty, Mona Mora Lucas whose body was found beheaded near our banding station. Every year we hear the sad cries and moans of her unsettled spirit- her head has never been found.

We ended up at the banding station to meet Raina and Colleen and watch the banding and release process. On our way to check the nets, we did see Mona's head and heard her tortured cries. Haunted spirits often hang out together, and goblins, ghosts and ghouls appeared around every tree, phantoms in the night.

Then - the owls descended! We brought to the station our first owl, then a second and third. Chirps, toots and wails were heard throughout the night. Were our guests excited about these petite, enigmatic, nocturnal predators? A picture says a thousand words. Steve King captured the group's awe in this last photo. Trish, who is holding one of the owls just before we release her, is truly taken as she touches her heart in complete amazement. The owl season has been incredible this year, with a total of 8 captured this night and 66 owls for the season as of this post.

Thanks to Steve and Raina King, Colleen Martin and JoAnna Arroyo for helping to make another great OWLOWEEN outing!

What is a OWL BIG NIGHT!?

2011-10-26T19:13:00.000-07:00

Well truly it depends on your location, because other stations have posted some incredible numbers (I will post about these later). For us at the BCCER we just had a BIG owl night on October 25, when a whopping 9 saw-whets were banded and released. Nice work Raina and Steve (with Steve's mom and saw-whet in photo below- the three Kings :)

This wasn't the biggest BIG night for us though - previous happenings occurred during our first year in 2005, on October 29th when 10 owls were captured and and again on November 4th 2007 when we banded 12 new owls and had 2 recaptures. Big owl nights are very exciting for us as it holds promise of a good year for owls. We always speculate on the event though, and typically fall to weather conditions like a high pressure system, waning-to-no-moon,and clear skies. These evenings are usually beautiful for star-gazing too and often accompanied by sounds of migrating geese and swans.

It could also be timing; being out on the right night when the the owls are flying through or have stopped on the Reserve to rest. But we can't know this unless we are out every night-all night during the migration period October 15-November 15. As of October 25th we are up to 34 owls for the season!

Following are the results:

Site: BCCER OWL2

Date: October 25, 2011

Weather clear: skies, gusty winds, 59*F

Net hours: 22.5

Banders/guests: Raina and Steve King, guests Kurt Geiger and children Maddie and Carter

Owls captured: 9 NSWO

Owls detected: NSWO throughout the night after the first hour

Thanks Steve King for photos.

Saw-whet Owl Season in Full Swing!

2011-10-23T07:41:00.000-07:00

Saw-whet owl season is off to a great start with our first bird captured on Sept. 28. After 2 more attempts of nothing, the owls began to fly; as of October 22 we are up to 22 owls. Compare this to our 2009 season when we had 23 owls the entire season!

Thank you Steve King for this saw-whet photo! She can be adopted. Go to the Adopt An Owl tab for more details.

Here are the 2011 results so far:

9/28 = 1 AHY/F

10/11 = 0 owls captured

10/15 = 0 owls captured

10/17 = 2 owls captured: SY/M, HY/F

10/18 = 4 owls captured: HY/F, 2 AHY/F, HY/M

10/20 = 4 owls captured: 3 AHY/F, HY/M

10/21 = 7 owls captured: 3 AHY/F, 2 HY/F, HY/U, AHY/U

10/22 = 4 owls captured: HY/U, 3 AHY/F

HY = hatching year bird, a bird hatched in 2011

AHY = After hatch year, a bird hatched before 2011

This year so far we have a 50/50 ratio of adults to hatching year birds. We like to see a high proportion of hatching year birds which indicates a high reproductive year for the saw-whets. We will see what the rest of the season brings.

First Banding Results Fall 2011!!!

2011-10-02T07:39:00.000-07:00

We netted our very first saw-whet owl on our first attempt this early season! Although we have been out on September 29th before, October 2nd is our first capture. Go here to see previous results. We did not hear any saw-whets vocalizing so we were very surprised to have one in our 3rd net run as we were getting ready to close. We also had a calling W. screech owl (female) and male great horned owl. There were lots of praying mantis on the nets and many crickets calling. Perhaps more food items for the rodent loving saw-whets- or at least their prey. here are the results from tonight:

Site OWL3-BCCER

Date: September 29, 2011

Weather: calm, clear, 75*F, new moon

Net Hours: 10

Banders: Garcia, R and S King, J. Arroyo helped- thanks!

Captures: 1 AHY/F N. Saw-whet Owl, 1 pallid bat

Let's hope for a great year in 2011!

2011-07-10T13:05:00.001-07:00

The Barred Owl - Spotted Owl cousin and competitor

Although my first great wildlife job was with the lovely, peaceful Spotted Owl (see last post), I also have quite a fondness for the Barred Owl (Strix varia), and why not, they are both interesting and beautiful large owls. I'm sure you will agree as you look at these pictures (this one taken by owl researcher and friend Jamie Acker who lives in Washington)

But here is the thing with the Barred Owl. They have expanded their range from east of the Rockies to the mountain ranges where the Spotted Owl lives - the Cascades and Sierra Nevada.

Being a habitat generalist (as opposed to a specialist like the Spotted Owl), and having much greater prey variety, they have bull-dozed their way through Spotted Owl habitat, first breeding with them (the offspring are called SPARRED Owls), and then displacing them.

When I lived on Bainbridge Island, WA, I met Jamie who was monitoring all the owl species on the island. I introduced color-banding and radio telemetry to his Barred Owl monitoring, and from that we became to know individuals, their habitat preferences and habits, and their offspring's dispersal. Their populations on the island continue to increase and they are very fecund, each pair having 2-3 young per year. This picture of a juvenile Barred Owl was taken this year by owl researcher Dale Herter, who I worked with in WA, conducting Spotted Owl surveys. We had only a handful of Barred Owl detections then, from 2000-2004.

In the Northwest, the Barred Owl populations have increased so greatly that in some forests- they will be managed for (killed) to help the federally threatened Northern Spotted Owl populations recover. I don't think this is a sustainable plan, because Barred Owls are savvy generalists, sort of like crows and coyotes, they are tough survivalists. But the other components of the plan (USFWS 2011) are more sustainable, and include better protection and restoration of Spotted Owl habitat (mature and old growth forests) and introducing fuel reduction and fire management, which opens the understory (important for Spotted Owl prey and hunting).

As with the Spotted Owl, Barred Owl's are quite personable. This is a pair of wild Barred Owls that Jamie is currently observing in his backyard on the island. The female, the larger owl is on the left and the male is on the right. In this picture they have molted all of their tail feathers so they look smaller than they really are. Their tail feathers will grow back in the course of 3 weeks to 1 month. Jamie and I published a paper, exciting for us, about Barred Owl rectrices characteristics and molt.

Jamie has also found that the Barred Owl preys on Western Screech Owls and is likely responsible for their demise on the island. Despite their competitive and invasive nature, it is hard not to have a fondness for the Barred Owls, once you get to them. Go here To see Barred Owls in action!

Spotted Owls

2011-07-01T17:38:00.000-07:00

Since the star of my blog- the saw-whet owl, is out of our project area for the summer, I will introduce you to another species- the Spotted Owl (Strix occidentalis). I was fortunate to have my first wildlife job in 1988 when I worked with the US Forest Service gathering baseline data on the Northern Spotted Owl (Strix occidentalis caurina- N. SPOW). Since, then the N. SPOW has been listed as threatened under the Endangered Species Act (1990) in Washington, Oregon and California, primarily due to loss of habitat (late successional forests), and in the last decade and second major threat - competition with the Barred Owl (Strix varia). The Barred Owl expanded its range from the east of the Rockies and is a larger, more aggressive and more opportunistic owl (in habitat and prey preferences) then the Spotted Owl. More on the Barred Owl later.

Working in Washington for a consulting firm for five years, I had the opportunity to help conduct a demographic study, where we located, captured, color-banded, and followed families of spotted owls and their young as seen in the photo above. These owls are amazingly tame and have incredible dark eyes. They are considered a large owl and primarily eat flying squirrels and wood rats.

The California Spotted Owl (Strix occidentalis occidentalis - CA SPOW) is found in our neck of the woods (the southern-most Cascade Range, Coast and Sierra Nevada Ranges) and is not currently listed (it is a CA species of special concern) although the Barred Owl populations are increasing here and becoming a threat to Spotted populations. I have worked with the CA SPOW for a several years for a consulting firm and currently for the US Forest Service. We are also monitoring their populaitons in the Sierra Nevada and documenting their reproductive success. To me, the subspecies are very similar in looks and behavior. The plumage of the CA SPOW is somewhat lighter than the N. SPOW which might you see in the picture below, a handsome male spotted owl - photo by my colleague Mary Muchowski. I do love my work!

Steve's Owl Recorder- the technical side of monitoring

2011-04-17T19:01:00.000-07:00

Steve King is one of the owl project's dedicated volunteers and brings his technical expertise to our program. Steve set up a remote broadcasting and recording device on the Big Chico Creek Ecological Reserve (BCCER) that he can monitor from his computer at home. Here is how he explains it.

The owl recorder is a device that can play a bird or owl call (in this case a N. Saw-whet Owl) and then record for a period of time after. The recorder can run completely unattended or can be commanded to play specific calls and record from anyplace with Internet service. The idea was to help us better understand when the Northern Saw-whet owl arrives and/or passes through the BCCER during migration. It was designed using a small low power computer. A USB audio input and output device was connected and a audio amplifier was also added that was capable of driving outdoor speakers. The picture above shows the recorder (and Steve) with the antenna on top, computer in the white box and the speakers down below. The battery is on the ground and the solar panel is behind the camera in a sunny location.

The call is played for 15 to 30 seconds and the recording is started right after the call ends. The time of the recording can vary. Once the recording is completed, it is sent to another computer over a wireless connection. The second computer is a little more powerful and it converts the audio wave file recording to a MP3 file and also creates a spectrogram of the audio recording. The spectrogram and recording are uploaded to a web page where we check for sounds. We can look at the spectrogram to determine if any sounds are on the recording. Below is a spectrogram after playing a Saw-whet Owl call, which shows a Saw-whet responding in a series of toots. The spectrogram and recording below was made in April of 2011.

Follow this link if you would like to hear the audio for the spectrogram. This was the latest detection for a Northern Saw-whet owl on the reserve for this season. There was a little wind that night, which shows up on the right of the spectrogram. There is also a highway in the area.

Pretty cool stuff! (comment by D Garcia)

Spring Migration- what do the years tell?

2011-03-31T15:56:00.000-07:00

Just recently we completed our NSWO spring sampling and ended up with a California Bat and no owls.

Most every year we - the owl team - make some efforts to determine when the N. Saw-whet Owl spring migration occurs in our area. We have nailed down the fall migration which occurs between Oct 1 and Nov 30, and peaks at the end of Oct, beginning of November. We also know that birds winter at the Reserves based on recaptures in winter months and telemetry locations in 2011. I would consider any February birds that we captured as wintering birds, with some possible movement at the end of February.

Over the years it appears that the birds move between the first and last week of March. 2009 was odd as we had a March 4 capture (could have been wintering) and an April 4th capture (our latest season capture). Using Steve's technology (a remote broadcaster and recorder) we have documented our latest detection on April 21, 2011!

Here are the data. Please note all of the 0 detection/capture nights and think about how dedicated my volunteers are to continue through the years.

2006

1/6/2006 (3 [2 and 1 recap] at BCCER)

2/7/2006 (3 [1 and 2 recaps] at BCCER)

2/22/2006 (0 at forest ranch)

3/7/2006 (2 at BCCER)

3/20/2006 (detections but no captures)

4/21/2006 (0 at BCCER)

4/28/2006 (0 detections/captures at BCCER)

4/30/2006 (0 detections at BCCER)

5/7/2006 (0 detections Magalia @2600')

5/12/2006 (0 detections forest ranch @3000')

5/16/2006 (0 detections at BCCER)

5/17/2006 (0 detections at Magalia)

2007

1/21/2007 (2 [1 recap at BCCER)

3/1/2007 (0 at BCCER)

3/10/2007 (4 at BCEP)

3/16/2007 (0 at BCEP)

2008

2/19/2008 (1 at BCEP)

2009

1/22/2009 (1 at BCEP)

2/28/2009 (0 BCCER)

3/6/2009 (1 at BCEP)

3/20/2009 (o captures but NSWO detection at BCCER)

3/23/2009 (3 at BCCER)

3/25/2009 (3 at BCCER)

2010

1/8/2010 (2 at BCEP)

1/8/2010 (3 [2 new plus 1 recap] at BCCER)

1/31/2010 (0 at BCCER)

2/18/2010 (0 at BCCER)

2/25/2010 (0 at BCCER)

3/4/2010 (1 at BCCER)

3/11/2010 (0 at BCCER)

3/13/2010 (0 at BCCER)

3/25/2010 (0 at BCCER)

4/4/2010 (1 at BCCER)

4/7/2010 (0 at BCCER)

4/21/2010 (0 at BCCER)

4/30/2010 (0 captures/detections)

2011

2/10/ 2011 (2 [1 new and 1 recap at BCEP)

3/7/ 2011 (3 [1 new and 2 recaps at BCCER)

3/29/2011 (no detections or captures at BCEP)

3/30/2011 (no detections or captures at BCCER)

4/12/2011 (bird tooting-heard on Steve's remote recorder)

recordings in between April 12 and April 21 accidentally deleted by me

4/21/2011 (bird wailing- heard on Steve's remote recorder)

Winter Sampling at BCCER - March 7, 2011

2011-03-09T08:04:00.000-08:00

On this winter night we set up our station at OWL3 at the BCCER. Past years have suggested that spring migration to the summering grounds occurs in early March when we have captured several owls in one setting. On this night serenaded by a great horned owl and numerous flocks of snow geese flying overhead, we captured three owls, but only one of these was unbanded. The other two owls had been captured three times previously, making this their fourth capture, an uncommon event. Our recapture rate is low and this is attributed to the birds being "net savvy;" once a bird is captured they rarely go back to the same site during the same season. These two owls seem to be "net happy," due to the high number of times they have been captured in the same season. It tells me that the audiolure is extremely attractive to some owls!

Here is their story.

Both birds were banded on October 15, 2010 during fall migration at the OWL3 site at BCCER. They are identified as band number 1014-14523 and 1014-14524, and although their band numbers are sequential, they were banded at different times that night. Each was captured on different nights two more times until March 7, 2011, when they were captured together again- this time during the same net run time. The number of days between capture is 149 days -close to 5 months, which is great evidence that the BCCER provides fine wintering habitat for these owls. Other research has suggested that siblings may travel together during migration, and although we can't say for sure, these birds could be siblings, based on the their capture patterns, see below.

Capture Date / Mass in grams / Sex (based on wing chord length and mass)

1014-14523

10/15/2010 84.3 unknown

11/1/2010 98.9 female

1/27/2011 84.9 unknown

3/07/ 2011 86.9 unknown

1014-14524

10/15/2010 95.4 female

10/16/2010 90.4 female

11/3/2010 97.2 female

3/07/ 201 93 female

Winter Sampling at Butte Creek Feb 10, 2011

2011-02-12T12:27:00.001-08:00

Several of us met at the Butte Creek Ecological Reserve (BCEP) to conduct a second sampling of wintering saw-whets in this area. In January 2011 we banded 6 NSWO, a record for this location in winter. Under a 1/2 moon and a starry night sky we sat listening to flocks of snow geese and tundra swans, canada and white-fronted geese, and a saw the dark silhouette of a great horned owl over our heads. We heard only a few saw-whet owl vocalizations and recaptured a bird of unknown sex (wing/mass measurements in the M/F overlap range) banded in January 2011, and one new Second Year female, her cuteness captured (above) by Steve King.

The following images/photo shows an aerial view/on the ground habitat of where we set up our nets at BCEP. Click on the image for a closer view of our net array.

Saying Farewell to HB - removing the radio harness

2011-02-06T07:07:00.000-08:00

Here you can see the location of HB's radio- somewhat obscured by her feathers- placed properly on her back. She has preened her antenna which is why it is kinked (Glenn photo).

Julie Shaw, CSU Chico grad student researching winter roosts sites of the saw-whet, called me and said "HB is low in a toyon, do you want to take her harness off?" HB is our remaining BCCER owl that still had a radio, for 91 days. Because the radios or so small (see earlier post "tracking the saw-whet"), they last only about 90 days-so we knew the battery would die soon. HB has been alternating in high (85') to low (3-6') perches and this day she was low. Although the radio harness or backpack is designed to bio-degrade, hers was still intact and I wanted to remove the backpack to set her free of any impediments caused by us. HB presented us with a perfect opportunity! Julie's trackers Glenn and Shannon took some of following photos-thanks!

Removing the harness

Step 1: find the bird. There she was about 6 feet high in a toyon shrub (Julie Shaw photo)

Step 2; Capture. There are many ways to capture a roosting saw-whet. I chose to use a capture technique where, with an extension pole, I place a coated loop around her head and wing. This immobilizes her temporarily while Julie then can hand catch her, as the second picture shows (Shannon photos).

Preparing to capture

HB is safely captured

And happily, Julie has safely secured HB (Shannon photo)

Step 3: Remove the harness. Next we find the harness material and clip it with scissors, and remove the backpack and radio. HB, in the second pic in this cell, is now free of her harness (Shannon photos).

removing the harness

harness-free

Step 4: check body condition. We want to check her body condition to see make sure the harness did not cause problems. Her keel (breastbone), felt fleshy on each side- indicating she was flying and eating well. We knew this though because Julie had found many pellets (regurgitated bones and fur/indigestible prey parts), and we alway saw urates below her roost, also indicating she was eating, thus hunting well. We checked her skin for potential abrasions from the material/radio- and fortunately there were none (Shannon photos).

checking the keel

checking the skin

We also weighed her and found that she was 97 grams, up 3 grams from her original mass of 94 grams! HB, a darling owl, who gave of lots of information about the wintering habits of saw-whet owls (Glenn photo).

Step 5: release. We released HB with high hopes that she would continue her success through the breeding season, likely somewhere in the Sierra Nevada Range, and thanking her for enlightening us to what habitats and prey (Julie collected almost 45 pellets that she will analyze for species composition) some saw-whet owls will take advantage of during the winter. These insights are invaluable for saw-whet owl conservation (Julie photo).

And as with any happy ending, we had a fantastic sunset as we exited the BCCER (Dawn photo)!

Those nestlings have BRANCHED

2011-02-04T20:08:00.000-08:00

Have you ever seen anything cuter? These sweet branchers ( an owl nestling who leaves the nest cavity and "branches" to nearby trees but is very dependent on parents) are the 2 kids that were mucking it up in front of the camera from their nest cavity (see them on video under the COOL LINKS tab). I received this photo from Tess McGurie who happened to be in our Snow Goose Festival "Owl night Out" event. She told me about this pic by Albert Boosman who photographed the branchers on May 21, 2010. Keep your eyes peeled for the petite fluffballs when hiking in the forests in summer!

OWL-NIGHT-OUT (SGF event)

2011-01-31T07:51:00.000-08:00

For the last four years we have conducted our Owl-night-out field trip for the Snow Goose Festival, a fine birding event held in Chico, CA. We hold the event at either of CSU Chico's reserves, the BCCER or BCEP. It corresponds to our "winter sampling" to see if the NSWO are wintering in the area. This year we held it at our OWL3 site at the BCCER. The nine participants were fortunate to meet two darling owls, both caught in the same net run.

They were both females hatched in 2010. One was a recapture from October 15th, which indicates she has been spending the winter (over 3 months) on the Reserve. Both owls were adopted (thank you Rich and Tess!), which helps support our fall monitoring project. Thank you to fine volunteers Raina and Steve King, Nancy Nelson, and Julie Shaw for the great night! All photos are Steve King's.

NSWO nestlings, a MUST SEE VIDEO!

2011-01-22T17:53:00.000-08:00

Check out the Cool Links tab. I have included a darling youtube video by Marcel Holyoak of NSWO nestlings looking out of their nest cavity. Careful, you will fall in love! This "teaser" photo is used with permission of Don Roberson (copyrighted).

Winter Sampling at the Dye Creek Preserve

2011-01-21T09:57:00.000-08:00

On January 20, 2011, Julie Shaw and I met with Preserve Associate Jackson Shedd, at the Dye Creek Preserve in Tehama County. The Dye Creek Preserve is managed by The Nature Conservancy (TNC) and is almost 38,000 acres in area. Our ongoing study to understand winter roost selection of saw-whet owls in the area led us to sample the Preserve. The habitat is quite different than our current sampling locations near Chico. The majority of the site consists of Blue Oak woodland and grassland, however Dye Creek is lined with dense riparian vegetation, similar to the Butte Creek Ecological Preserve (see post A Winter Sampling...). The big difference is the lack of winter over-story vegetation from conifers and Live Oaks. Although Live Oaks are scattered in the uplands lining the creek, most of the vegetation is deciduous (the image below shows full leaf out- not winter). But, due to our telemetry study with Julie, we know NSWO select low dense shrubs and Live Oak trees to roost; both components of the Dye Creek Preserve habitats. We figured they just might be roosting along the creek. In these two images you can see the Dye Creek site (upper) and an expanded view of the three sampling sites, Dye Creek, BCCER (higher elevation), and BCEP (lower).

We set up for two hours under a clear sky dotted with stars. An almost full moon came up near the end of our monitoring session. During this time we never detected or captured a saw-whet owl. Based on my experience if NSWO are in the area they will likely respond. I interpret the nights lack of response to mean there were no saw-whet owls using the area during the sampling period. We will try again! We did have a night full of sound, coyotes singing, and many flocks of Tundra Swans and Snow Geese flying overhead. Plus, we captured a Western Screech Owl, released by Jackson Shedd (photo by Julie Shaw).

New Post under "What's in a Name" tab

2011-01-19T17:09:00.000-08:00

What does birdbling mean? Look at this owls leg for a hint.

Where did the name "Saw-whet Owl" come from?

go to the NSWO - What is in a Name? tab for the answers!

A Winter Sampling of Owls

2011-01-17T21:24:00.000-08:00

One of our monitoring goals is to sample the NSWO use of CSU Chico's reserves (equate similar habitats in our area) during the winter. This past weekend, four of us went to the Butte Creek Ecological Preserve (BCEP), located off of Honey Run Road- of off the Skyway. The preserve habitat is very disturbed because the creek was heavily mined. Mine tailings comprise the uplands but on those grow chaparral and mixed hardwood/conifer (oak/grey pine) species. Riparian scrub and forest line Butte Creek. The elevation only about 330' elevation, all and all quite different than the BCCER site. But, we know owls use this preserve based on my previous banding efforts as well as an actual visual. Click the photo above left to see an aerial view of our net array.

This picture below shows the actual lane where we erect our mist nets at the BCEP

On Friday January 14, 2010, we set up just after sunset to the trilling call of a Western Screech Owl. We began to hear many saw-whet vocalizations; toots, twitters, wails and chirps, and knew it would be a good night. Indeed! In just 2.5 hours we captured and banded 5 NSWO, more than we had in any previous winter. The were all owls hatched last year, and all female. The high number of wintering owls does make sense because we had such a great fall season (92 owls!) in 2010. So, the BCEP and proximate area, is providing good prey and winter habitat for the young owls. To see more about the Preserve, hiking trails and birding, click here.

Updated Post!

2011-01-13T09:24:00.000-08:00

Check under the Monitoring tab for updates today: Ageing the Saw-whet owl!

Logistics of banding and tracking

2011-01-05T13:51:00.000-08:00

Yes, it is very exciting to have a NSWO in the hand and also to see one in the wild, like this one! And it isn't easy. Both federal and state permits are required to capture and band birds, and install telemetry. I have these permits only after a lot of training and a project that has scientific merit. My training consists of 16 years of banding, several banding workshops and meetings, and most recently a training session to install telemetry. I met with NSWO researcher, author and conservationist, Scott Weidensaul who has conducted telemetry and geolocator studies in Pennsylvania supported by the Ned Smith Center for several years. Here I learned a safe and efficient way of making a harness that will "break away," after about 3 months, leaving the owl without its backpack or radio, and giving us about 3 months of information regarding roost locations and movement of our owls. (I took this photo of "Dos," she is one of our radioed owls).

And that is our study of scientific merit. You will note that so little is known about the NSWO in the Pacific States, that our banding and telemetry studies will help us better understand the ecology of the NSWO in this region- new and exciting stuff (and necessary knowledge for conservation measures)! This picture shows two dedicated volunteers (Raina King and Colleen Martin) banding and taking measurements of the a NSWO (photo by Steve King) during our fall monitoring project.

See the previous post for a pic of the harness and radio and a map of one of our owls movements to Bidwell Park. And don't forget to go to the Adopt -an-Owl tab, to become a guardian of one of our banded and released (and adorable) owls!

Tracking the Saw-whet

2011-01-04T07:54:00.001-08:00

Our fall monitoring project has expanded to have a new component- radio telemetry and tracking. I am helping a CSU graduate student Julie Shaw, with her studies to determine winter roost sites of the saw-whet. One of our questions derived from the fall monitoring was, "where do the birds go in the winter after migrating through the Reserve?" We knew that some stayed

on the Reserve because we recaptured a few, a couple of weeks to

months later.

But now, because we have installed tiny radio transmitters on the owls (3 grams total, less than 3% of the birds body weight-see picture above that includes radio and harness material), we are able to track them to their actual locations! Julie will collect 2 years of data and then publish her results, brand new information for our region- and wonderful to better understand the ecology of our population of owls! So far we have found owls roosting on the ground like this bird,

some a few feet off the ground, and many way up in a tree- up to 85 feet, so all we see is a feathery ball, like in the picture (the bird is within the red circle).

We always like to get a good look if possible to check the condition of them and make sure their harness is fitting well. The harness will come off in about 3 months- the same time as the life of the radio battery. Most of the birds sit in good cover to protect themselves from diurnal predators like Cooper's Hawks. We got a really nice look at this bird who has had her transmitter on for 8 weeks.

Julie has been great about creating maps of the bird's locations, like this one. Here you can see a map with 4 different roost locations of one bird who was banded at the Reserve and then moved

down into Bidwell Park.

NSWO prey items

2011-01-01T21:15:00.001-08:00

2011-01-01T18:27:00.000-08:00

Most studies looking at pellets (the fur and bones remaining from eaten prey that an owl will regurgitate, often before flying off to hunt again), show that small rodents make up a high percentage of the NSWO diet. You can imagine how great it is to have a rodent hunter like a saw-whet around! This photo is a pic I took of an actual NSWO pellet.

Julie Shaw (CSU Chico graduate student) and trackers are tracking owls to their roost sites. Roosts are a great place to look for pellets and Julie will collect and analyze these. This is incredibly important because around here, there is no documented or published information about what the NSWO eats during the winter. But personally I have seen a NSWO sitting on a deer mouse (3 times) and a meadow vole. If you look closely at the picture below, of a bird we named "Lucky", you can see she has a large grey blob in front of her- a meadow vole!

Other prey items that saw-whets take include many small mammals like shrews, pocket mice, red tree voles, and even juvenile chipmunks and squirrels! Small birds are taken mostly during their nocturnal migrations and even some insects like beetles and grasshoppers. I took this information from the Birds of North America series for the NSWO, Cannings 1993, but you can go and subscribe online to this excellent resource!
Sometimes these small owls can't eat their whole prey, and eat them in pieces. If their is too much for one meal they will either cache the leftovers somewhere safe, like a crook in branch, or they will roost on top of it. What better way to have a warm dinner?

The Adopt an Owl Certificate

2010-12-23T20:56:00.000-08:00

Our adoption program is exciting! Please see our first adoption certificate created for the woman who generously funded our start-up project. As part of our Adopt-an-Owl program, we also have created a wonderful brochure that describes our project, how you can be involved, and how to adopt owls for you, your friends and family. Check this out!

Adopt-an-Owl program launched December 2010!

2010-12-18T15:07:00.000-08:00

This year Altacal Audubon Society has developed an "Adopt-an-Owl" program to help support the Northern Saw-whet Owl fall monitoring project, now in its sixth season. This exciting new program allows an Adoptive Guardian to adopt one or more of the banded or radio-marked owls that we have captured during our ongoing project. The guardian will receive a certificate with their adoptive owl showing the unique band number, age, sex and date of capture and banding. A brochure is also included in the packet telling more about our program. If a radio-marked owl is selected for adoption, the receiver will get continued updates of their owl. Our owl certificates make unique gifts! Your donation helps support our continued research and is tax-deductible. (saw-whet owl photo by Mel Richardson)