With spring in full swing we have officially wrapped up our winter raptor field season. Both Middlebury and Goodrich have been reliably checking in and sending location data for us to analyze. So far each bird has revealed drastically different movement patterns. 

Middlebury seems to be a true migrant. As he is a Northern subspecies, we would expect him to travel to Vermont for the winter and then return north to Canada in the spring to breed. This appeared to be the case when he crossed the border into New York on March 25th and flew about 30 miles north by the end of the day. From there he began to meander north making a stop at the Ausable Marsh Wildlife Management Area along the way. He then flew another 30 miles north to Kings Bay Wildlife Management area and was within three miles of the US-Canada border on March 30th. He then abruptly changed course and headed back south and ended up back in the Ausable Management Area where he is as of today. It is unclear what caused him to stay in New York and if he will stay there for the summer. As long as he continues sending locations we can continue to follow his journey and see where he may end up. It will be interesting to see if he comes back to Vermont this summer or next winter. 

Goodrich on the other hand appears to be a year round resident. His territory appears to be firmly established and has not changed at all. He was even noted perching on the same tree he was first encountered on several times throughout the winter during subsequent survey days. His longest trip away was about a mile south to another field and then quickly back to his favorite patch of woods. His patterns may change throughout the summer and may reveal that he is nesting in the area. Several other red-tails were observed in the same area and may be his mate. Future surveys might determine the location of a nest. 

We will continue to post updates on our birds throughout the summer!

The post Winter Raptor Research Updates From the Field – Season Wrap Up appeared first on Nature Blog.

The last few weeks have been excellent for winter bird watching. Since our transmitters are arriving later than expected, we’ve decided to change strategies and set up standardized survey routes. While we’re mostly focusing on raptors, we love all birds and can’t help but stop and watch some of the large flocks of winter birds we’ve been seeing too. 

We’ve talked a lot about red-tails so far, so we wanted to share some information about the other birds. The second most common raptor we see on our survey route is the rough-legged hawk. Rough-legged hawks are in the same genus as red-tails (the Buteos) and get their common name from feathers going all the way down to their toes! This is one of their adaptations for breeding in the chilly arctic. In the winter these raptors migrate down to southern Canada and into the US. Like the red-tails, they also have different “morphs” or color patterns. Some are lighter in color with a broad dark belly band and patches where the wing bends. Others sport a dark brown plumage with light-colored flight feathers and a white band on the tail. We have seen a wide range of these morphs throughout Addison County.

Another winter bird we love to see is the snow bunting; we’ve seen these birds in flocks of hundreds. Snow buntings breed in the high arctic, and during the breeding season have an all-white plumage to blend in with the snow. In the winter, snow buntings change into a black-and-white plumage with rusty patches to blend in better as they scurry across the gravel roads and snow-covered fields.

Mixed in with the snow buntings we have also been seeing many horned larks. From far away they may seem plain and are sometimes difficult to see. Their brown plumage blends in well with soil and vegetation on the edges of roads. However, a closer look will show they have a sunny yellow face, thick black mustache, and tiny feathers that stick up like horns, making these birds look like quite the character. While still quite common, horned lark populations have had a dramatic decline over the last few decades which is certainly a cause for further study and conservation.

We have also seen common redpolls this season bouncing in big flocks across the fields. Redpolls are a type of finch that breed in the far north. They primarily eat small seeds like birch and alder and will happily drain a feeder full of nyjer or thistle. In winter, common redpolls have been known to drop from trees into the snow below to make a tunnel. Though it may seem counterintuitive, the snowpack actually provides some extra insulation during cold nights.

We have certainly been enjoying the excuse to get outside, breathe in the fresh air, and appreciate some of nature’s beauty brought from other parts of the world. As you can see, many of these birds will be leaving us soon to make the long trek up to their breeding grounds. Have you gotten a chance to go out winter birding yet this season?

The post Winter Raptor Research Updates From the Field – Week 3 appeared first on Nature Blog.

We’re still waiting for all our materials to come in, but that hasn’t stopped us from getting in the field. We went out recently for another round of trapping with our partner from Cornell, Bryce Robinson, to find another abieticola (a subspecies of red-tailed hawks). 

Similar to our prior outing, we didn’t catch a bird until late in the day. Just as the sun set over the fields, our research coordinator Jim made one more attempt before we called it a day and this beautiful bird came to the trap.

The rich colors on the wings and belly indicated this could be a good candidate to put a transmitter on. However, bird safety is our top priority and we decided there wasn’t enough time left in the day to release before dark. So we took some measurements, gave it a blue band reading “OS” and sent it on its way.

Our second day out we found a rather interesting bird. We spotted a red-tail hovering over an old carcass and dropped the trap. It came to the trap rather quickly and as Bryce removed the bird from the trap he was delighted, but torn. The “globby” dark belly band suggested this individual was very likely an abieticola, but it was a young bird. As we noted in our previous post, the goal of his study is to put transmitters on birds that will be breeding in the far north. Since this was a younger bird it might not breed this upcoming season. So once again, we took measurements, gave it a blue colorband (OR), and released it.

The last day reminded us that sometimes you find what you’re looking for in unexpected places. We finally caught an ideal candidate, not on the expansive farmland, but near a golf course just outside of Middlebury Campus. With rich streaking, a nice dark belly band, and plenty of daylight left, we put our second transmitter out with the colorband “OB”. Of course, this meant we had no option but to name this bird Obi-Wan.

With that, our trapping has come to a pause. Until we get our units in we will continue to note where we see raptors to get a greater understanding of the distribution and abundance as winter progresses. We also search for our color banded and GPS mounted birds while in the area. With limited cell service both Goodrich and Middlebury have not sent locations in some time, but both were spotted during an outing yesterday. This confirms that they are healthy, and that the transmitters are still properly attached. Check back for more updates soon.

The post Winter Raptor Research Updates From the Field – Week 2 appeared first on Nature Blog.

For the past few weeks, our research team has been searching for Red-tailed Hawks throughout Addison County in preparation for trapping. While this gave us a good idea of where to look, we quickly learned that it is important to stay flexible, and most of all, patient. 

To catch the red-tails we use something called a Bal-chatri (or BC) trap. Like much of the foundational knowledge and tools we have on raptors, these types of traps originated from falconry. BC traps can be traced back to falconry in east India where horsehairs were tied as nooses around cane cages with live prey inside to lure the raptors in.

Modern versions of these traps substitute hardware cloth for the cane and fishing line for the horsehairs. In order to trap a raptor, live prey is placed inside the hardware cloth cage to entice the bird to come to the trap. As it attempts to snatch the prey, tiny nooses surrounding the cage entangle the raptor’s talons so it can’t fly away.

In order to maintain everyone’s health and safety, we split up into different cars and had two teams out looking for birds. When we saw a bird we wanted to try to trap, we slowly drove by, dropped the trap in view of the raptor, headed down the road to wait. More often than not the raptors ignored our attempts and we’d drive on to the next bird. After hours of searching, we finally had a taker.

Just before sunset this beautiful bird came down to our trap. For the Red-Tailed Hawk Project, they are specifically looking for adult breeders of a Red-tailed hawk subspecies called abieticola which breeds in more northern regions. This bird had some of the darker markings indicative of that subspecies. However, looking closer at the feathers, we concluded that it is only a second-year bird and so may not breed yet this year. We decided not to put a transmitter on this bird, but still gave it a color band for potential re-sighting opportunities and released it. This bird received color band Blue – OK.

The next day temperatures were low and it seemed the birds were even more hunkered down than the day before; no luck for us. On day three our patience finally paid off. With the first drop of the trap we captured a richly marked bird and decided to deploy our first transmitter.

Using Teflon ribbon the transmitters are carefully attached to the birds like a backpack. The transmitters record GPS points and when the bird is in range of a cellphone tower, all the GPS data are downloaded. This will allow us the opportunity to see where Goodrich ﹘ the name we gave the bird for the area it was trapped in ﹘ goes both in the winter and during the breeding season. Goodrich received color band Blue – 1U.

We are still waiting for some materials to come in before our trackers are ready to go out but in the next few weeks we’ll be trapping again with the Cornell team to find one more for their project. Check back soon for more updates!

The post Winter Raptor Research Updates From the Field – Week 1 appeared first on Nature Blog.

By Jim Armbruster – Research Coordinator

Addison County Vermont is the place to be for birders. Its mix of unique habitats draw hundreds of birds and bird watchers alike. In the winter it is known for being home to several migratory artic species including Rough-legged Hawks, Snowy Owls, and thousands of Snow Geese.

Other species also call this area home in the winter including Red-tailed Hawks. Red-tails are known to be partial migrants in Vermont. Birds from the northern parts of their range will move south for the winter. The timing and length of their travels are reliant on several factors. These migratory birds may displace residents that are migrating themselves or may leap frog areas with a resident until they find a suitable spot for the season. Some Red-tails remain residents in Vermont year round. Some may leave the state entirely. The migration strategies are well known but their use of this region is less studied.

The goal of our winter raptor ecology project is to determine how Red-tailed Hawks are using the habitat in Addison County. We will look at the timing of their migration, movements in relation to changing weather conditions, and abundance in relation to prey availability. We also hope to find the relationship between migratory and resident Red-tails that will coexist for the winter season and potentially the relationship between Red-tails and other similar species like Rough-legged Hawks.

To accomplish these goals we will map the size of our ten study birds home ranges through the winter to determine what factors drive the size and location. We will mount radio telemetry trackers on eight of our study birds and then relocate them throughout the winter.

We are also partnering with researchers from Cornell in their Red-tailed Hawk Project to mount GPS trackers on two birds. This data will aid in our project and help their researchers to look at the breeding success of Red-tails throughout their entire range.

Next winter we hope to partner with researchers from The Idaho Cooperative Fish and Wildlife Research Unit in their Rough-legged Hawk Project. This will include mounting GPS transmitters to Rough-legged Hawks while they are in Vermont for the winter. The transmitters will provide year round movement data for those birds.

The data collected this winter can be used to build the framework for more studies in this area. GPS trackers on all our birds can give us a year round look at their movements. We can determine where exactly these winter migrants are coming from and where they end up once in Vermont. Several seasons of data can be used to look at other factors influencing their decisions. Other species like Rough-legged hawks can be added to the study to look at the relationship between two similar species that share the same habitats in the winter.

Stay tuned for more updates from the field!

The post Winter Raptor Research in Addison County appeared first on Nature Blog.