Tuesday, December 21, 2010

How can you not love waxwings?

In preparation for our upcoming birding trip to Belize, I thought I should take in some sunny weather to practice using our new camera. Remembering the Cedar Waxwings from the Christmas Bird Count, I headed to Dry Creek Cemetery. I found the waxwings and a few other birds, but the Varied Thrush remained elusive. Waxwings are definitely one of my favorite birds.

Cedar Waxwing.

Cedar Waxwing.

Cedar Waxwing.

Two Red-tailed Hawks flew overhead, one chasing the other. The chasing bird retreated to the top of the highest tree and proceeded to exclaim that this was his territory. Mating season may still be months away, but a productive territory is always worth defending.

Adult Red-tailed Hawk.

Monday, December 20, 2010

Counting the birds for Christmas

Yesterday I participated in the Audubon's 111th Christmas Bird Count. It was the 44th Christmas Bird Count held in Boise.

The Christmas Bird Count is an important long term study of bird populations across the country. Since it has amassed such a large data set, it has been a critical resource for assessing bird populations and distributions over time. This makes it the most significant citizen science project currently underway.

In communities across the country, volunteers spend an entire day counting every bird they can find. The count is restricted to a 7.5 mile radius from a chosen central point. The Boise count is centered in the Idaho State Capital. About 30 people showed up at 7am on a Sunday morning under snowy skies and nasty roads. The "count circle" was divided by the organizers into a number of sections. I paired up with two other volunteers I didn't know and headed out into the snow surveying a section of NW Boise. It's a great way to meet new people.

The skies lightened up a little bit around sunrise providing a great start to the counting. Hundreds of Canada Geese, American Wigeons, and of course the ever present invasive European Starlings. The species racked up quickly. About an hour into the count, Sue's car died. Dead battery. We flagged down some help to get a jump start, but we definitely needed to move on to plan B. We retreated to Gary's house so he could borrow his son's car. Unfortunately Sue had to leave us for the day.

Gary and I headed to Dry Creek Cemetery. Lots of bird action here - Cedar Waxwings, Red-Breasted Nuthatchs, Cooper's Hawk, Sharp-shinned Hawk, and then I found a Varied Thrush. The Varied Thrush is a great bird to find! Dang, my camera was back in the car. I went to get it, but the thrush was gone when I returned. The lighting wasn't too great for photos anyway.

Cedar Waxwing.

Cedar Waxwing.

Adult Cooper's Hawk (maybe second year).

Next up was Hidden Springs. Only about half of Hidden Springs is within the count circle. We had to check it out as some rare birds had been seen there is previous weeks. No rare birds, but we did get some good species such as Western Screech Owl and Great Horned Owl. The snow started again, somewhat mixed with rain. Along Pierce Park we found a life bird for me, a Northern Shrike. In fact we found two! This was a great find for the count.

Northern Shrike.

In a particular group of trees, I thought I had heard a Northern Pygmy Owl. We searched and searched, even played their call on an ipod. No response. Then I saw a Townsend's Solitaire. Gary played the solitaire's call and that was it. It's very close to the quality of an owl. I realized I had never heard their call. The pygmy owl would have been a great bird, but so is the solitaire.

Moving back into the Boise neighborhoods, the rain slowly picked up and visibility dropped. We continued counting, but the new species declined. I had to leave at 3:30, so Gary continued on his own. When I left him we had counted 40 species for the day and thousands of individual birds. I won't have the totals of the whole Boise count circle for a few more days, but I expect the number of species to be near normal, which is usually around 80 species.

Wednesday, December 01, 2010

Rare Visitors and Snow Days

The talk of the birding community within Boise for the past week has been the presence of two very rare warblers in Idaho. I first received the call on Thanksgiving Day just before dinner with my in-laws. This was not the best time to go running in pursuit of a few lifer birds. Or maybe it was, but I chosen to maintain family relations instead. The following day we left for a weekend in Sun Valley. I had mostly forgotten about the birds until receiving word yesterday that they were still around. I decided that Wednesday afternoon would be my chance.
Wednesday morning we awoke to about 7 inches of new snow and still more falling from the sky! This is an unusual amount for Boise. Shortly before heading to school I received a text message from the University indicating that classes were canceled. It was time to go birding! Since all the wimpy drivers stayed home, we had no problem making it down to the river.
Would the birds still be around with this much snow? Would they be hiding? Karyn and I's first walk through the snowy area failed to find anything but House Sparrows. Walking down river there were plenty of Canada Geese and Mallards. We could hear Belted Kingfishers in the distance and then the call of a Bald Eagle.
Juvenile Bald Eagle, probably 3rd year.
Walking back to "the spot", we noticed some small birds moving through the trees. I pull up my binoculars and there it was, my first ever view of a Yellow-throated Warbler! This bird is only the 3rd report ever in Idaho. I moved in for a photo, but none was to be had. I lost him. I continued searching until I found the other rarity, a Northern Parula! Lifer #2! This is only the 12th report ever in Idaho of a Northern Parula. I had to get a photo.
The bird would not hold still. It was moving through the branches foraging. I was juggling binoculars and the camera to try for a shot. The viewfinder was covered in snow. I couldn't tell if the camera was focusing or not. At one point the Parula was chased by a Ruby-crowned Kinglet. There he was still on a branch! Snap.
Northern Parula!
Dang, missed him! Another attempt.
Northern Parula.
Warblers are sooo hard to get wild photos of. Finally.
Northern Parula.
We searched some more for the Yellow-throated Warbler, but we never located it again.

Sunday, November 28, 2010

Playing in the Snow

Winter has arrived in Idaho. It came quickly with very cold weather and plenty of snow. Karyn and I had planned to hit Sun Valley last weekend, but it didn't work out. We did make it on Friday for three great days of cross country skate skiing. I can definitely feel it throughout my body as I sip my brandy on this Sunday evening. But it wasn't all about skiing. We headed out Saturday afternoon in search of wildlife. While we missed some of the spectacular rare birds which showed up in Boise (Northern Parula and Yellow-throated Warbler), we did get a good look at a number of my favorite winter birds.
I saw my first Rough-legged Hawk of the season. Apparently it is a good year for Rough-legged. They are regular winter residents of Idaho, but some years their numbers are very high. I only saw one but other reports total into the hundreds for a single day! Next on my list of favorites are the Snow Buntings.
Snow Bunting near Ketchum Idaho.
They are usually found in flocks, but this guy was solo. Another year round favorite of mine is the American Dipper. I love watching them diving in the water, but it is even more spectacular in the winter with the snow and ice. We saw more than a dozen on Warm Springs Creek.
American Dipper near Ketchum Idaho.
Even though I am a bird nerd, we do like other wildlife as well. We would see hundreds of Elk, a few dozen Mule Deer, a couple of Coyotes, and Karyn snapped this photo of a friendly Beaver which entertained us for 30 minutes.
North American Beaver, Warm Springs Creek.
Great skiing, great wildlife, and great food made for a great weekend together. Now its back to school for a few more weeks.

Sunday, October 31, 2010

The Northern Goshawk!

It's been a great and busy fall as I continue to get settled into my Master's Program in Raptor Biology at Boise State University. The great news is that my top candidate thesis project received funding from the forest service! I will be studying breeding ecology of Northern Goshawks. Focal areas include the prey base in a uniquely structured forest, prey's effects on nest productivity, and some work on sex ratio of the offspring. I am very excited about that. While the project is funded, it is not fully funded so my past few weeks have been filled with applying for additional grants. Oh yeah, in case I wasn't busy enough, I also have my classes and teach my labs.

Another activity filling my time this fall was being trained on trapping and banding raptors. My thesis does not require migration trapping, but I wanted to gain the handling experience which I will need during the breading season. The Idaho Bird Observatory, where I have worked for 2 years, operates two raptor trapping stations, one at Lucky Peak (location of songbird banding, owl banding, and Hawkwatch) and one on Boise Peak. These locations are chosen to align with the flight paths of migrating raptors as they move down the Boise ridge. Both stations reside near the tops of mountains between 6000 and 6500 feet. I spent most of my time at Boise Peak. It is more difficult to get to in a vehicle, but my enduro motorcycle makes easy work of the rough roads. While Boise Peak isn't quite as successful in total numbers of birds trapped as the Lucky Peak station, it does offer its rewards in great views, close up action, and fewer people. The bird I most wanted to catch, the Northern Goshawk, did grace my presence on a number of occasions. On the first occasions I was still being coached on the process. Dave instructed as the goshawk dialed in on the prey from a mile away!

My first goshawk! A juvenile male.

One thing you quickly learn about goshawks is that they are much higher strung than any other bird we catch. A non-stop "I want to rip your eyes out" sort of intensity. They are also very powerful! They are forest raptors making them very maneuverable. They can catch birds in flight, pick squirrels out of trees, and even capture large items such as Snowshoe Hares or jackrabbits. This one really wanted my pigeon!

The trapping station consists of a blind with a series of nets and lures. The nets and lures are all operated by strings. The lure birds, all non-native species, wear harnesses which allow us to pull them up into the air so that they flap their wings. The harnesses also protect them from attacks from the raptors. We use pigeons to attract birds from far away and to capture the larger species, Eurasian-collared Doves for middle size prey, and House Sparrows for the smaller raptors. Some nets are spring loaded bow nets on a string trigger and some are vertical nets positioned in front of the lure birds.

Boise Peak Blind and Sparrow Traps.

Pigeon trap (far right), Dove trap (near left).

View from inside the blind.

Raptors in the hand provide a unique way to learn the subtleties of the species. Most of the species that I caught belong to the family of Accipiters. These are all highly maneuverable forest species. The male Sharp-shinned Hawk is the smallest bird we catch, even smaller than an American Kestrel.

Juvenile male Sharp-shinned Hawk (~100grams).

All of the Accipiters, and most all raptors in general, exhibit reverse sexual dimorphism. This means that the female is larger than the male. There is a correlation of the amount of dimorphism and the speed of their prey. Since Accipiters capture fast prey, including birds in flight, the females are much larger than the males, up to 80%!

Adult male Sharp-shinned Hawk.

Another thing to notice from the two pictures above is that adults have very different plumage than the juveniles and their eyes change from yellow to a rich dark red. While eye color cannot be used to provide a definitive age, other observations tell me the adult pictured above was at least 2 years old (we call it "after second year" on a scale of: hatch year, second year, after second year). Sharp-shinned Hawks and Coopers Hawks look much alike. A large female Sharp-shinned is almost the same size as a small male coopers. They both have different juvenile and adult plumage and the eyes change from yellow to red. One very distinguishing feature is the shape of the head. Sharp-shinned have very small heads, where coopers are much more blocky.

Adult male Cooper's Hawk (~250 grams).

Adult female Cooper's Hawk (~470grams).

Juvenile female Cooper's Hawk.

Adult male Cooper's Hawk (probably 2nd year-note eye color).

Which brings us back to the largest North American Accipiter, and the baddest of the bad, the Northern Goshawk! After my first "coached" trapping of a goshawk, I would have a number of good solo experiences as well. On my final day in the blind this year, I would successfully trap three goshawks! I missed the first and another flew by un-interested, for a total of five sightings. A biologist friend of mine, Julie, and her husband would join me in the blind for this remarkable day. Within 15 minutes of their arrival I demonstrated how its done by catching the first bird. The video linked below was taken by Julie's husband John.

Julie with juvenile male goshawk (~850grams/2 pounds).

Juvenile male Goshawk.

But that wouldn't be all. A short while later we would catch another male, this one had much more white than the first.

Male juvenile goshawk.

Male juvenile goshawk.

Male juvenile Goshawk.

But the day wasn't over yet. A third goshawk, this one a big female, went for my pigeon.

Female juvenile Northern Goshawk (~980grams).

Female juvenile goshawk.

Weapons of mass destruction.

Amazing birds!

What a way to finish out the season. I really enjoyed my days on the mountain. I now spend my time writing grant proposals so I can spend more time with the birds!

Sunday, September 12, 2010

Graduate School and Field Work

My whirlwind year has continued as I just completed my third week of graduate school. The last few weeks have been filled with going to school, learning to teach, trying to solidify my thesis proposal, spending time doing field work, and fitting in as many mountain bike rides I can before the end of summer.
School - As a graduate student in Raptor Biology, my course load is somewhat light. The emphasis of the program is on the field work. I am taking two core classes plus one seminar. The core classes include Biometry (Biological Statistics) and Raptor Ecology. The seminar is focused on Animal Behavior. So far the workload of all three has been fairly light. I have one additional class for the first half of the semester focused on teaching. This is required for all students receiving a teaching assistantship.
Teaching - As mentioned above I received a teaching assistantship. This assistantship provides free tuition, health insurance, and a small salary in exchange for teaching biology labs. I currently teach two 3 hour labs per week. The labs are for freshman and sophomore biology majors. It is essentially the second semester of general biology. The lab spans nearly all life forms in a single semester, covering bacteria and archea, protista, fungi, plants and animals. In addition to my teaching time I sit in another teachers lab to better learn the material, attend a weekly coordination meeting, hold office hours for students, and prepare material, quizzes, grading, etc. In all it consumes about 15-16 hours per week. I am really enjoying the assignment. The classes are both good with engaged students who ask lots of questions. There are always a few who aren't paying attention and then require more special assistance, but I have been impressed with most of them. I had my first quiz at the end of last week, so this week promises to include many discussions about how I graded it and if there are extra credit opportunities. The bottom line is that I was generous on the grading and I don't believe in extra credit. I am sure they will call me a hard ass.
Thesis - This is the core of my graduate studies. This semester I need to create a detailed proposal for my graduate research. This includes learning the necessary background material, identifying the unique contribution to science, justifying the work, designing the experiments and field methods, and lining up any necessary funding. Early next semester I must present my proposal to the department for approval. This will be followed by two years of field work carrying out those experiments, then writing and defending my thesis. Right now I am investigating two different topics in parallel. The first is dependent upon funding from a federal agency whose budget is not likely to be solidified any time soon. The second is a continuation of some of my undergraduate research into the migratory timing of raptors and songbirds focused on optimal foraging theory. It will be very nice when I can drop one and just focus on the primary proposal. Any chance congress will pass the budget before January? Not too likely... Wow, I've got a lot of work to do...
Field Work - While I don't have the field work for my thesis yet defined, I am continuing to improve my general avian field experience by continuing my work with the Idaho Bird Observatory. I spend at least 1 day a week in the field working on avian migratory projects. Last year during school I worked on hawk watch, counting migrating raptors as they pass over the monitoring site. This year I am working on banding raptors and learning how to trap them for banding. So far my work has been on extracting them from the nets and banding them while being instructed on trapping. Jesse, another IBO employee, wrote a great blog article explaining the trapping process and sent me a number of pictures that he took.
I'm extracting a Sharp-shinned Hawk from a DG net. Photo by Jesse.

Extracting Sharp-shinned Hawk from DG net. Photo by Jesse.
The general trapping process includes using a number of different types of nets and a number of different types of lure birds. The lure birds have harnesses which allow a string to be attached and also provides them protection from the attacking predators. Pigeons play the rule of the larger lure to bring in raptors from farther away. Eurasian-collared Doves are the final prize for larger raptors while House Sparrows play the role for the smaller raptors. A pull of a string causes the lure bird to fly up in the air and attract the raptors.
On my second day in the blind, Jay lured in a juvenile male Swainson's Hawk! While they are common in the area, this is only the 4th Swainson's banded here in 15 years. The first in 10 years! I had the honor of extracting him from the net and banding him. They are rarely caught during migration as it is believed that they migrate all of the way to southern Argentina without eating. Amazing! Either that's not entirely true or this was a local bird still foraging because he went after the dove in a spectacular dive!
Juvenile male Swainson's Hawk. Photo by Jesse.
This time of year we mostly catch juveniles for most species. The adults generally migrate later. The true reason for this hasn't been completely established, but it is believed that the adults can stay on the breeding grounds longer even though prey populations are declining because their hunting skills are better. In some species the adults also molt their feather before migration where juveniles are still wearing their juvenile feathers during migration. This also explains why some males migrate at different times than females of the same species. The sexes can have different molt strategies as well. Most raptor species show reverse sexual dimorphism (female larger than male). In some cases the size difference with quite substantial (50% bigger). This enables the two sexes to utilize different prey bases which can also lead to different migratory times. It's all interrelated - did dimorphism cause separate food niches which caused different migration timing, which caused different molt strategies, or did different molt strategies cause different migration timing, which required dimorphism? Hmmm. The joy of analyzing causation in ecological studies. My opinion = yes. It's all interrelated.
I'm applying a leg band to juvenile male Sharp-shinned Hawk. Photo by Jesse.
During the banding process we not only attach a leg band to the bird, but measure wing, tail, weight, eye color, crop, and parasites. These measurements must be performed while staying very wary of the bird's main weapons. The talons and bill are very sharp and warrant the utmost respect. The Red-tailed Hawk picture below sunk his talon into my chest as I was repositioning him. Ouch! The species differ in their attack as well. The American Kestrel is a ruthless biter and a master at wiggling his short tarsi free to grab you. The larger hawks seem to just use their talon and grab anything that touches them. Neosporin is my friend!
Juvenile male Red-tailed Hawk.

Juvenile female Cooper's Hawk.
My first experience with actually running the trap came unexpectedly. On a really slow day in the blind, my instructor took a quick break to run back to camp. Just after he left I see two Sharp-shinned Hawks cruising by. This was my chance. I pull the Pigeon. One of the Sharpies (short for Sharp-shinned Hawk) peals off and dives toward the trap. I switch to the sparrow. I grab the string, but the bird doesn't respond as I expect. The sharpie loses interest and flies off. While I had been instructed on the general operation, I had never actually pulled on the strings. It looks easy but requires much more finesse. My first opportunity would go unfullfilled. I am looking forward to next Wednesday for another chance. I will also spend a little more time practicing the pull of the string for each lure.
Songbird banding is still operating at full speed. With school and the above mentioned activities keeping me busy, I am not regularly working with songbirds, but I did spend a few hours up there on Saturday. I was able to band my first Townsend's Warbler of the year, a favorite of mine. They generally come through in September after the start of school so I have had little opportunity to see one up close this year. We had a Townsend's, a Wilson's Warbler, a Nashville Warbler, and a MacGillivray's Warbler all at the same time. Cool.
Juvenile female Townsend's Warbler.
As you can see I have plenty to keep me busy. I am still trying to mountain bike with Karyn 4 days a week and have to resubmit my undergraduate research manuscript for publication. In all, it has been a great 3 weeks and I am looking forward to the next three years in this program.

Wednesday, August 18, 2010

That was fast...

After completing my Flammulated Owl surveys early in the summer and taking a little time off, I have spent the last 4 weeks banding songbirds at the Idaho Bird Observatory's Lucky Peak site. The time flew by and that assignment is now complete, although the team will be banding until October 15. This week I am at school orientating for my new masters program in Raptor Biology and my teaching assignment which begins next week.
It hasn't been all fun and games. In addition to banding songbirds I have been completing the data entry for the owl surveys (completed this morning), updating the final report on our owl season (still work in progress), updating my undergraduate research manuscript for resubmission to The Condor (ornithology journal, completed on Monday and distributed to my reviewers), and performing background research on my potential master thesis projects. Wedged in between we have been mountain bike riding, camping in the woods to pick huckleberries (good season), etc. It has definitely been a busy 4 weeks!
The masters thesis work is progressing. My lead project would be working on the breeding ecology of Northern Goshawks within the Sawtooth National Forest. It would be an excellent project, but I need to find some money to fund it. My second choice, requiring fewer funds, would be to study predator prey relationships during autumn migration. This would be a continuation of my undergraduate research. I am meeting with my thesis committee next week to flesh out more of the details of both options.
In a previous post about songbird banding, I covered the process and some of the work involved. I thought I should share some other interesting experiences. When cold weather first arrives in Idaho it is often a shock to these small bird species, especially the juveniles. When we are processing a cold bird we will occasionally put them in our shirt to warm them up. Last year, I had a juvenile Ruby-crowned Kinglet that didn't want to leave. A few weeks back, on our first really cold morning of the season, I had another Ruby-crowned Kinglet friend. I first should say that the Ruby-crowned Kinglet is one of the smallest birds, other than hummingbirds, that we process. They weight roughly the same as 1 US quarter. After processing a juvenile bird, I released it in my hand. The bird did not fly away but instead climbed my jacket up to my shoulder. I walked over and sat down. The bird remained. Everyone went to get their cameras and returned to take a picture. It was a good 5-10 minutes before he/she flew off.
Juvenile Ruby-crowned Kinglet on my shoulder.
Speaking of small birds, we occasionally process hummingbirds as well. We do not have a banders permit for hummingbirds, but we do take basic measurements before releasing the bird. We just don't catch enough of them to focus on banding. The Calliope Hummingbird is the smallest bird we catch at 2.5 grams (1/2 weight of US quarter), but we also catch Rufous and Black-chinned Hummingbirds which are about 50% larger.
Me processing a juvenile female Black-chinned Hummingbird.
Since juvenile Rufous and Black-chinned Hummingbirds are difficult to distinguish, especially females, we often have to consult the reference books to be sure we have a correct identification. The books also help on other species in identification, aging, and sexing.
Checking in reference book for positive ID.
Hummingbird feathers are so thin you can actually see right through them. It is amazing that these birds can fly 10's of thousands of miles.
Juvenile female Black-chinned Hummingbird.
I will still spend more time up at the bird observatory, but on a less regular basis and on a mixture of activities. For example, I will probably train the new hawkwatch crew next week (counting migrating raptors overhead as they migrate) and I look forward to spending time in the hawk trapping blind after we begin hawk banding next week. I still encourage people to go up and visit. It is a great experience.

Tuesday, August 03, 2010

Summer is "flying" by

Here it is the beginning of August. School starts back up in just a couple of weeks!
After completing the owl surveys earlier in the summer, Karyn and I took a much needed vacation to the Stanley Idaho area. There we hiked, mountain biked, and admired wildlife. Upon our return I started working up at Lucky Peak banding songbirds for the Idaho Bird Observatory. I call it work, it is really volunteering. Karyn refers to it as my summer camp! This activity continues their 15 year work in studying avian migration. It was the basis for my undergraduate research into the weather effects on avian migration and supports many other important studies as well. This is the second summer I have worked there. Its hard to believe that its already week three in my four week assignment there. After that I return to school for a week of teaching assistantship orientation and then the fall semester begins! Wow, where did the summer go?
Banding songbirds is a great way to learn a lot about birds. Not only does it help with identification, but also the birds life history and ecological requirements. Songbird banding at Idaho Bird Observatory begins in mid-July and continues through mid October. Hawk banding begin in late August and continues through the end of October. The songbird nets operate for the first 5 hours after sunrise every day. We currently have 4-6 people working each morning.
The focus of the banding activities is on avian migration. Early in the season we mostly catch local birds which are dispersing through the area, but there are a few migrants coming through. To catch these few migrants we must start as early as mid-July. The Lucky Peak banding site is considered a stopover site. Migratory birds stop there to refuel before continuing their long journey south. Just before migration begins, they experience a hormone change which causes them to enter hyper-phagy (eating a lot). Their body also shifts to load up on fat to fuel their journey. We can tell that a bird is migrating or getting ready to migrate by examining its fat stores, one of the many attributes we measure on each bird banded. The first "loaded" bird I banded this year was a beautiful male Bullock's Oriole heading south. We only delayed his journey for a few minutes...
Bullock's Oriole heading south!
Many people talk about how hard it is to identify birds in the wild. This is illustrated very well when it becomes difficult to identify birds in your hand! Some of the most confusing that we handle are the flycatchers. The difference between a Dusky Flycatcher and a Hammond's Flycatcher is very subtle. Sure, there is the primary projection rule, but what if the bird is a juvenile that is still growing its tail feathers? Bill size? There are differences, but they too are subtle. Then its gets down into the details ... such as primary feather #10 in a Dusky is longer than feather #5, about the same in a Hammond's. Now memorize these rules for the 100+ species we catch at Lucky Peak and there is always lots to learn. A while back the "Western" Flycatcher was split into the Pacific Slope Flycatcher and the Cordilleran Flycatcher. We do catch a number of westerns, but which species is a quandary. The reference guides say we only have Cordillerans here in Idaho, but all that we catch measure up to be Pacific Slope. Hmm. For now we just call them Westerns...
Hammond's Flycatcher (l) and Western Flycatcher (r).
Some species just make it easy. There are no mistakes with the male Lazuli Bunting. I love these birds.
Male Lazuli Bunting.
Once past the identification of species, we measure wing chord (length), tail length, fat score, muscle score, feather molt and wear, try to identify the sex, and the age. Sex is easy in some birds and just not possible in other species. Age is also a very tricky determination. Its usually easier to tell hatch year from after hatch year, but determining second year from after second year can be a challenge. In most species the birds don't molt all of their feathers during the second year, but in the third year they will replace all flight feathers within a very short period. Thus, to age the bird we try to analyze the flight feathers to determine if they are of different ages. If they are of different ages, then the bird is likely a second year, if the feathers are all the same age, the bird is likely an after second year (can't age beyond this). Making this more difficult is that different species will have different approaches to feather replacement. Lazuli Buntings are unique in that they replace their outermost primaries and innermost secondaries, but not the ones in the middle during their second year. This is illustrated in the photo below (it is rarely this obvious!).
Molt limit in male Lazuli Bunting.
You can see the outermost 6 feathers are darker (newer) than the next 5 feathers, then the next inner feathers are also newer. The primary coverts (small, short feathers "covering" the outermost flight feathers) are also old. These wear slowly so it makes sense to use them as long as possible. Growing new feathers is a very expensive process.
We often catch juvenile birds which might still be fed by their parents. Under these circumstances, we quickly process and return the birds to where they were caught. We often get to watch as the parent immediately feeds them. Its pretty cool. If we catch birds of the same species together, then we process them and then release them together. Yesterday, I extracted 4 juvenile Black-capped Chickadees from the net. We processed them and then delivered them back to the area where they were caught to regroup with any others they might be marauding with.
Juvenile Black-capped Chickadees.
The Idaho Bird Observatory is located east of Boise Idaho on top of Lucky Peak. We welcome visitors. Come by and check us out.