Friday, May 27, 2011

Two weeks in, three weeks behind...

Here's an update on the progress I have made during the second week of my field season. I have previously posted an introduction and summary of the first week. As you might be able to determine from the title, the field conditions continue to provide unexpected challenges. With that said, I am still optimistic looking forward as some early signs of spring are beginning to reveal themselves in the area.

The return to the study area for the second week was filled with optimism. Having seen a male goshawk in a particular territory and receiving some updated information on where the nest might be, we were excited to go find it. We first checked in on one of the previously discovered nests just to confirm that she was still incubating. She was! So we headed on our way. The road was snow covered, but looked doable. A couple of hundred meters down the road, we changed our minds... I tried to back out, but couldn't make it. We had to turn around. This is where it all went horribly wrong. The front end slid into the ditch. We were stuck.

Lapse of judgment!

The truck was equipped with two shovels (luckily), but the only other equipment we had was a floor jack (not so luckily). After working for 2 hours with these tools, we determined that better equipment was needed. We would walk back to the cabin and hope for the sheriff or forest service to come by in the next day or two. At least I had my motorcycle to get around. Good thing our territory was within hiking distance. Just after arriving at the cabin, the forest service enforcement officer (Kirby) stopped by! He took a look at our vehicle and said that he couldn't help. He suggested that we cover the Boise State door sticker with a University of Idaho door sticker and leave it there until the snow melted, which has to be within a few days... He did lend us a high rise jack (widow maker) before going on his way. Not wanting to ruin the entire day, I sent Lauren on to the territory while I worked on getting the truck out. Two hours later, it was free. I hiked down to join Lauren in the search. Hours later we had racked up 3 additional nests, but none of them occupied... It was a bust.

Next up, the Albion mountains! Its a pretty good drive out of the South Hills and in to the Albions. Luck was still not on our side. The first territory was high on a ridge across a raging stream. Just the night before, a flash flood had occurred wiping out half of the road and cutting a deep channel. The water was still raging and not offering us a safe crossing. We passed for the day and moved on. The next territory provided easier access, but when we found the nest tree it was not occupied. If this trend continues I will definitely be facing small sample size issues! We returned to the South Hills empty handed.

About mid-night we awoke to a banging noise outside. It appeared that someone was stuck in the Magic Mountain parking lot. There is a huge mud hole there. This would be the second vehicle in a week. Lauren suggested that we go see if they needed help. I wanted to make sure that we did not become over committed, but since we did have a radio that could reach law enforcement, we could offer that. As we walked down toward the vehicle we noticed the sheriff was already there. In fact, the sheriff was helping to pull the vehicle out. Hmm. The other vehicle was also a sheriff! This story was getting better!!!

Sheriff Kelly in mud hole being pulled by Sheriff Steve and ourselves.

We had previously met Sheriff Steve (pulling), but not Sheriff Kelly (stuck). Steve was happy to see us and the help we could provide. Kelly was a little less happy that the audience had expanded, but also welcomed our assistance. We returned for our truck and within ten minutes, he was free. I think this earned us a "Get out of jail free card." I am willing to bet that this isn't that last vehicle that will be stuck in the South Hills this spring.

Our new friends - Steve and Kelly.

Wednesday - two new territories to cover. Lauren was signed up for a ten mile round trip hike over the snow ridge to check on one of our occupied nests and to search a new territory. I had a 1.5 hour each way motorcycle ride to my territory (had to ride out of and around the South Hills). This could possibly provide access to another territory as well. The first territory was beautiful - a mix of Aspen and Lodgepole Pine. I would see a Wild Turkey, a White-tailed Jackrabbit, a Coyote, lots of woodpeckers, Mountain Bluebirds, Red-tailed Hawks, Ravens and an unbelievable number of Ruby-crowned Kinglets singing to their hearts content. Unfortunately, I would not find a goshawk nest. I tried to get to the second site another four miles further up, but snow drifts once again prevented my passage. Lauren would also come up empty on the day for her territory. Ouch.

Typical South Hills Goshawk Territory - Aspen, Lodgepole Pine, Sub-alpine Fir, Sage.
Lodgepole Pine Maze.

The news wouldn't get any better on Thursday. Our plan was to drive around the west side of the forest and camp there to access five potential sites. These sites are only 10 miles from our cabin, but the snow prevents vehicle access over the ridge. We awoke to three new inches of snow on the ground! When will it stop?!? Once we hit the gravel roads on the west side, we knew we might be in trouble. They were saturated and very muddy. As we drove higher and higher, the conditions worsened until we decided not to risk going further. We sat there in frustration for 30 minutes before heading back out of the hills and on toward home. Defeated for the week... No new nest sites... Very little progress in our searches... Frustration...

I have pondered a few of my learnings so far. The most obvious choice is to start the season later next year. Of course, next year the snow may melt weeks earlier (average melt is three weeks earlier than this year). A second thought is to design a project that is less dependent upon timing. Utilizing nest cameras to quantify prey consumed requires early access. The first cameras could be installed as early as next week. My other methods and questions do not require as early access. A third point has been the low quality of the historic data on which I depend. Some of the coordinates for the nest sites I have are in the middle of a sagebrush field. Clearly not even close to a "nest tree". Next year I will of course have much higher quality and more recent nest site data - mine. Some literature speaks to the high degree of nest site fidelity, but I have received word from other researchers with contradictory data. A review of the past research also notes that a large number of nests are blown out of trees and some of the historic trees are no longer standing. I expect that another limiting factor is our ability to detect the nest. Nests located in Aspen are fairly easy to see and locate, especially now before the leaves come in. Nests in Lodgepole Pine however are much less conspicuous. I imagine that our skills will improve with time. One of the challenges within the South Hills is the very large amount of parasitic mistletoe. Each mistletoe ball looks like a nest structure from a distance. Unlike many other raptors, Goshawks build nests below the canopy which is where the mistletoe also grows.Mistletoe in Sub-alpine Fir is very easy to write off, but in Douglas Fir or Lodgepole Pine it requires closer inspection.


We have a big week ahead. We will start broadcasting goshawk calls which will greatly improve detectability. Before the first of June broadcasts are discouraged due to the stress placed on incubating birds and the fact that they are less responsive before the eggs hatch. We will return to each site where we failed to detect a nest and use the broadcast search protocol. We will also begin our prey surveys. These surveys involve hiking a 750 meter transect in each territory and counting each potential prey species - ground squirrels, chipmunks, jackrabbits, and many bird species. Using a laser rangefinder we will measure the perpendicular distance from the transect to each individual mammal or bird. The resulting values, along with several repeat transects, will be used in a statistical procedure to produce a prey abundance estimate for each territory. These prey abundance estimates will then be compared between territories as predictors for occupancy and nest productivity. Lastly, I HOPE HOPE HOPE for access to the rest of my study area! If this occurs we will have more work to do than we can possibly complete! That would be awesome!

Saturday, May 21, 2011

Great Horned Owl v Snake

While waiting for a prey delivery to the Cooper's Hawk nest, I watched a Great Horned Owl dive on a snake. I repositioned to get a better angle and caught this in flight. The snake looks to me to be a Racer.

Great Horned Owl with snake (Racer?).

Thursday, May 19, 2011

First week starts with a bang, ends in snowy frustration but renewed optimism

The first week of my master's thesis field season studying Northern Goshawks was a mixture of stress and anxiety, ecstatic discoveries, frustration, and disappointment. A year's worth of planning all came together for a successful week that fell short of expectations. I was not surprised by this. Last week I posted a quote predicting that my plans would undergo significant challenges and it indeed came true. The good news is that we did make progress (discovered two occupied goshawk nests), we learned along the way, gained renewed confidence in my field methods, and we have a renewed plan of attack for next week.

My study area is in the South Hills, a portion of the Sawtooth National Forest located south of Twin Fall near the Idaho/Nevada border. Since the study is partially funded by the Sawtooth National Forest, they have generously provided us lodging in the small cabin picture below located on Rock Creek in the South Hills. My field assistant Lauren, myself, and other occasional volunteers will be staying there. It sure was nice the first week as the outside temperature dipped to 16 degrees and snow was falling much of the time.

Our home for the next eight weeks.

For the first few days Lauren and I were joined by Karyn (my wife), by Jay (Idaho Bird Observatory Research Director and my thesis committee chair), and Heidi (Idaho Bird Observatory researcher and BSU Graduate Student). After our arrival in the South Hills and an evening cleaning the cabin, which had been closed up all winter and possibly for a few years, we headed out on the first morning to find our first goshawk nest. I had been given rough coordinates for a number of historic goshawk nest locations and we chose one which looked to be easily accessible.

Heidi, Jay, Me, and Lauren navigating through our first territory.

While it snowed much of the night, the first morning was clear and cold. The cold crusty snow enabled us to hike without snowshoes. We worked our way toward the expected nest location. Once we were within 100 meters of the assumed location, we split up and began the detailed search. Just one minute after splitting up I looked up and right there in front of me was the nest! It was occupied! I can honestly say that I haven't felt that excited in some time. It was such a rush. Three years of preparation for this new career, one year of planning on this project, and less than one hour in the field and I was staring into an occupied nest! I used hand signals to tell the others I had found the nest!

My first view of the nest tree in front of me!

Female Northern Goshawk on the nest.

Wow, this was easy. Only 24 other historic territories to go. As you might expect, it doesn't always work like this. We moved on to the next territory. This involved a one mile hike on snow, occasionally post-holing, followed by a thorough search of the area. With five people for two hours we were not able to find a nest. Finding this particular nest in this territory was supposed to be easy. We decided to move on as we could ask for more specific directions later from individuals who had been to the nest. That afternoon, in a third territory, we again failed to find the historic nest. Some of these nests haven't been looked at in the past eight years. The original GPS coordinates could be as much as 200 meters off. This might not sound like that great a distance, but in dense forest, post-holing in snow, the effort to find a single nest in a single tree is definitely considerable.

Discussing search strategy with Heidi.

A new days brought new nest searches. Unable to cross the ridge due to deep snow we drove for 2 hours around the outside of the forest to gain access to the west side of the mountain range. On the drive we saw a male goshawk perched on the ridge. We bailed out of the truck to observe and mark the location.

Me, Laruen, Heidi, and Jay observing goshawk on the ridge.

Our first search of the morning was rewarded with our second occupied nest! Jay discovered this one. Surprisingly, this nest was occupied by a sub-adult female (one year old bird). Sub-adult females are able to reproduce, although sub-adult males usually are not fertile. I am definitely liking this morning success. Should we just take the afternoons off?

In second territory search on the west side of the mountain we were able to find the historic nest, but unfortunately it was not occupied.

View over territory.

Lauren scanning for nests.
Jay and I overlooking territory as the clouds roll in.

The lack of an occupied nest caused some lapse of focus as Lauren and Heidi started inspecting the lichens on the rock, which was also covered in Marmot scat. Do you think a goshawk could eat a marmot? Hmm.

Fungus nerds (Lauren and Heidi) inspecting the lichens.

The storm hit as we headed back to the cabin for a meeting with the wildlife biologist from the forest service. In fact, I had driven this road three days in a row and it had snowed there every day.

Snowing in Rock Creek.

On the third day it was left to Karyn, Lauren, and I as Jay and Heidi had their own projects to get on to. With new information we returned to a territory from the first day. The three of us systematically searched the area again for 2.5 hours. We did find an unoccupied nest, but it mostly likely belonged to a Red-tailed Hawk as it was near the top of the tree and open where goshawks prefer to nest under the canopy.

Lauren and I inspecting coordinates on the GPS.

A few days before we had seen an adult male goshawk fly from a stand of trees about 700 meters from our documented nest location. Karyn suggested that we go search there. I said no as we have a search protocol which would eventually take us there, but we first had to find the historic nest. As the fog came in and the snow decreased visibility we headed in for the morning. I would later receive updated information from the forest service that in recent years the nest has been located in that very stand of trees that Karyn proposed searching. I guess Karyn has earned a significant number of "I told you so's". We will head there first thing next week!

With limited road access, the amount of snow on the ground, and a forecast of more snow in coming days, we made the decision to abandon our work for the rest of the week. We will return on Monday, hopefully to better access and higher productivity. This first week was filled with the excitement of finding the nests, with frustration of only being able to access about 1/4 of the study area, and relief that I believe my field methods in general are going to work. I am now excited to return to the area on Monday morning.

With the amount of time we spend in the field, we are able to observe other wildlife as well. One species of unique interest in the South Hills is the South Hills Crossbill. This bird is a sub-species of the migratory Red Crossbill which has taken up permanent residence in the South Hills. There it has evolved a unique morphology which has resulted in it being proposed as its own species.

Male South Hills Crossbill.

The South Hills lack tree squirrels, so the South Hills Crossbill has taken over the role of the pre-disersal seed predator of Lodgepole Pine. As a result the Lodgepole Pine has developed a unique defense in its cone structure to protect against the Crossbill seed predation instead of the usual squirrel seed predation. In the evolutionary arms race, the Crossbill has in turn developed a unique bill structure to overcome these new defensive mechanisms. This has driven the bill structure of the South Hills Crossbill to be different from the standard Red Crossbill. These birds are abundant and easy to see in the South Hills. Interesting stuff!

Male Northern Harrier.
Short-eared Owl.
Very awkward looking Sandhill Crane on a nest.

We have seen and heard many other bird species and have watched the increased emergence of the Belding's Ground Squirrel which are key prey items for the Northern Goshawk. I look forward to our return to the field early next week.

Saturday, May 14, 2011

The Study Begins

After a year of proposal writing, planning, and presenting, the first field season of my Master's study in Raptor Biology is about to begin. Yesterday I finished the spring semester of my classes and tomorrow I will be heading for the hills, the South Hills that is. For the next 8 to 9 weeks my field assistant and I, along with other volunteers, will be performing a range of field studies all pertaining to my study species, the Northern Goshawk. The purpose of my study is briefly explained in my project abstract.


Forest structure has a profound impact on the species communities which live within its boundaries. The size and shape of a forest plot, the unique plant composition, and the proximity of the forest plot to other plots are among the factors influencing the species composition and dynamics over time. Anthropogenic impacts, both direct and indirect, can disrupt or accelerate the dynamic processes within a forest plot further shifting the species composition. Understanding how species utilize naturally fragmented habitat and how they respond to changes within that habitat can provide greater insight into their ecology and help prioritize management decisions to aid in conservation. The Minidoka Ranger District of the Sawtooth National Forest of Idaho, with its discreet forest segments and unique flora and fauna, presents unique challenges to sensitive species such as Northern Goshawks. The naturally fragmented forest structure found in the Minidoka Ranger District exhibits the constraints of island biogeography. The top identified food source of Northern Goshawks worldwide, tree squirrels of genera Sciurus and Tamiasciurus, are naturally absent from these forest islands. Additionally the Aspen forests upon which the Northern Goshawks locally depend are under threat from historic fire suppression practices and global climate change. I propose a multi-year thesis project to explore the breeding health of the local Northern Goshawk population by studying territory occupancy rates, breeding success, and fledgling sex-ratios relative to habitat quality, territorial prey abundance and predicted forest structural changes. The results will provide forest managers with information on the state of the Northern Goshawk population within the Minidoka Ranger District and the most significant factors affecting successful breeding within the population.

Much of our field time will be spent searching for Northern Goshawk nests. We will be visiting historic nests and checking for occupancy and systematically searching for new nests. We will be installing a total of six nest cameras to quantify what they are eating. Yes, tree climbing skills are critical. For each territory we will perform prey surveys every two weeks, counting every potential prey species observed. We will monitor the nest success and productivity, then lastly document the habitat structure of the nest stand.

All of this collected data will be processed over the next six months to answer the key research questions mentioned in the abstract. During this time, adjustments to the field processes will be developed for my second field season next year, when I will be doing it all over again.

As we head out to start this field season, a few challenges await. First and foremost is that the snowpack is two weeks behind average in melting. This follows many years of it melting earlier than average. The result is that there is still 36 inches of snow across much of the study area. We will be using snowshoes to start the season and some territories will just not be accessible. I am worried that previous studies have shown a very low nest occupancy rate in heavy snow years. The snow wasn't as heavy this year (only 20% above normal), but stayed much longer (snow pack now is over 200% of normal). I have a detailed day by day plan for the first week, which is now moot due to snow. I haven't even set foot in the study area and my plans are already out the window. This reminds me of one of my favorite quotes:

"In preparing for battle I have always found that plans are useless, but planning is". -Dwight D. Eisenhower

Lets hope my planning has enabled me to respond to these new challenges. And so I begin this journey with tremendous excitement and an open mind to let the season play out before me. What I do know for sure is that it will be a fantastic adventure. I will try to provide updates, although they will likely be brief.

Project is funded in part by a Challenge Cost Share agreement with the USDA Forest Service, the Mike Madder's Field Research Award, and Boise State University Raptor Research Center.