SPEARFISH — A small group gathered for a closer look as South Dakota State University ornithologist Dr. Kent Jensen identified, banded, and documented birds Thursday and Friday at D.C. Booth Historic National Fish Hatchery and Archives.

Karen Holzer, Booth Society executive director, said that that hatchery is very fortunate to have Jensen visit, describing that he is onsite twice during the summer months.

“He always takes time to explain the whys and hows of the bird banding activity to individuals helping and those watching,” she said. “The bird banding activity is an excellent educational opportunity for interested people to interact and participate.”  

Jensen, whose main research interests are in the ecology and habitat use of grassland birds, including upland gamebirds and waterfowl, set up nets around the hatchery grounds to catch birds to band, and one of the birds he netted Thursday was a male ovenbird, a small songbird of the New World warbler family.

Jensen explained that the bird gets its name because its nest is built on the ground, and with the dome and side entrance, the nest resembles an old earthen oven. 

“They’re hard birds to see because they stay in thick cover,” he said, adding, “These are gorgeous little birds when you start looking at them closely.”

Jensen pointed out the light-colored ring around the ovenbird’s eye, its orange-colored cap, and heavy spots/streaks on its breast. He added that ovenbirds are quite territorial and have a recognizable “teacherteacherteacherteacher” sounding call.

“They’re really loud for a little bird,” he said, adding, “This one is so photogenic.”

Jensen said that the first thing to do after catching a bird in the net is to identify what type of bird it is, followed by what size of band he needs. The bands are made out of aluminum, and he has specialized tools to use in attaching the band to the bird’s leg and take some measurements, like weight and wing length.

This information is then submitted to a database. Jensen is permitted through the Bird Banding Laboratory (BBL), an integrated scientific program established in 1920 supporting the collection, archiving, management, and dissemination of information from banded and marked birds in North America. According to BBL’s website, the information is used to monitor the status and trends of resident and migratory bird populations. “Because birds are good indicators of the health of the environment, the status and trends of bird populations are critical for identifying and understanding many ecological issues and for developing effective science, management and conservation practices,” the website explains. The BBL, in collaboration with the Bird Banding Office of the Canadian Wildlife Service, administer the North American Bird Banding Program, which manages more than 77 million archived banding records and more than 5 million records of encounters, and each year, approximately 1 million bands are shipped for use in the United States and Canada, with nearly 100,000 band encounter reports submitted. 

Jensen explained that the bands range in size from very small up to larger sizes for eagles and other birds of prey. He said that they are aluminum — except when dealing with birds that live in saltwater, as saltwater corrodes aluminum very quickly and therefore stainless steel bands are used in that situation — and it does not matter which of the bird’s leg is banded.

Each band is individually numbered with a nine-digit code, “like giving it a Social Security Number,” Jensen said. 

Earlier in the day, he caught a black-capped chickadee which had a band on its leg that he had attached the year before, and he explained that since chickadees don’t migrate, it’s likely that many of them live their whole lives on the hatchery grounds, so it’s not uncommon to catch a chickadee that he’s already banded during his annual visit. Jensen estimated it is his 10th summer visiting the hatchery to band birds.

“It’s such a beautiful setting,” he said, adding, “Today’s perfect weather for this.”

While working with the birds, Jensen utilizes a “bander’s grip,” with the bird’s head between his index and middle fingers. That way, he said, he can move the bird around and take the measurements he needs, looking at different parts of the bird, while it is safely nestled in his hand.

“It’s not getting hurt; I’m not getting hurt,” he said, adding that the chickadee he caught earlier in the day was much more rambunctious, biting and scratching, than the ovenbird.

“They’re pure attitude,” he said of chickadees.

Jensen also banded and documented a female house finch Thursday, and he showed a few “tricks of the trade” to the group gathered. While one can often identify males and females based on their different colors of feathers, Jensen demonstrated how blowing on the bird’s belly, to allow for the parting of the feathers to see its skin beneath, could also provide clues. If a bare, wrinkly spot of skin, called a brood patch, is visible, the bird in question is a female. A mother bird uses her brood patch to put against eggs to incubate to maximize the heat transfer, Jensen said. 

He also checked the bird’s wishbone area, as that is where fat accumulates when bird are putting on weight. He explained that it is yellow in color. None was visible on the bird Thursday, which made sense, Jensen said, because the only time they accumulate fat is when they’re getting ready to migrate.

“It’s like they’re filling their gas tank up,” he said. “Otherwise, they don’t carry extra fat because it would be inefficient for flight.”

Jensen also looked at the finch’s skull. He said that just like human babies, bird skulls don’t completely ossify until they’re a few months old. He wet his finger to use to part the bird’s head feathers to look at the skull, and if the bone hasn’t filled in, it will look deep purple in color, so he can tell birds that were hatched this year because of that color. While Jensen couldn’t say the exact age of the finch, he knew that she wasn’t hatched this year, because her skull was fully ossified. 

“This little girl is ready to go … none the worse for wear,” he said after taking the finch’s measurements.

Then the group was off to keep checking nets to see what other birding discoveries could be made during Jensen’s time at the hatchery.

“We appreciate the dedication and knowledge Dr. Jensen shares during the bird banding activity,” Holzer said.

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