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Phenology Report: Time to scrutinize a bird nest

A bedraggled nest composed partially of discarded plastic hangs in a small shrub. The nest was found on Feb. 13, 2024 in Bloomington.
David Murphy
A bedraggled nest composed partially of discarded plastic hangs in a small shrub. The nest was found on Feb. 13, 2024 in Bloomington.

Phenology workshops

Upcoming Workshops with John and Charlie: Feb. 13, 2024

John begins the report with good news: there are a lot of ways to connect with him and other phenologists in the few weeks! John is hosting two workshops on Saturday, Feb, 17 at the Back to Basics conference, put on by Season Watch sponsors Happy Dancing Turtle. The keynote speaker and vendor fair are free and open to the public; please be sure to register for workshops.

Two short weekends later, John will be guiding nature walk (more likely a guided amble, given all the interesting things to see) during the tenth Minnesota Phenology Gathering. The gathering is from March 1-3 and is hosted by our friends at Long Lake Conservation Center! As you can imagine, John is quite excited to get together with other phenologists and nature experts. Registration is due by Feb. 28, and 1.5 CEUs are available for attending teachers.

I hope you can join us! you can find upcoming workshops here.

A mysterious, trashy nest

Ol’ J-Lat was particularly taken by a report of a birds’ nest partially constructed with plastic. Our Bloomington-based student phenologists found it last week while on their phenology walk, and asked John which bird might make such a nest.

Latimer on Great Crested Flycatchers: Feb. 13, 2023

A Great Crested Flycatcher perches on a branch in Bloomington on July 20, 2023.
iNaturalist user tederake
A Great Crested Flycatcher perches on a branch in Bloomington on July 20, 2023.

John thinks the bird responsible could be a Great Crested Flycatcher. I strongly recommend you listen to his impression of one, which I've embedded to the left.

These birds build their nests with a slithery little secret component: shed snakeskins. In areas where snakes are abundant, you’d be hard put to find a nest without a snake shed somewhere in it. (In one Florida study, all 46 GCF nests studied contained snake sheds!)

A later study tested if the addition of a snakeskin to a nest affected the survival of the young. Their results* showed that shed snakeskins can deter some nest predators, particularly mammals like flying squirrels.

According to the Cornell Lab of Ornithology, just 75% of nests in cooler climates contain snakeskin. One factor could be the relatively smaller population of snakes in northern regions. Instead, the birds supplement their nests with shiny or wrinkly objects like white tree bark, onion skins, or – you guessed it – plastic litter. (For some reason, I didn’t find a study examining if bedraggled zip-loc bags deter flying squirrels yet.)

So, did our student phenologists come across a flycatcher nest?

All of the initial evidence was affirmative. However, at the time of recording, John didn’t have one crucial piece of data: a photo of the nest, showing where it was found.

Great Crested Flycatchers are cavity nesters like woodpeckers, House Wrens and chickadees. They raise their young in enclosed spaces like hollow trees, artificial nest boxes, or – according to Life histories of North American flycatchers, larks, swallows, and their allies by Arthur Cleveland Brent - “Any old tin can or box they can find.” (Trash birds!)

However, the photo the students provided shows a cup nest in a tree, similar in structure to those built by robins. Does that rule our beloved flycatchers out? I sent John the photo to see what he thinks, so we’ll find out more next week!

Other information:

Other topics in this week’s report include:

  • A gigantic flock of waxwings that visited Bemidji last week (time stamp 1:53) 
  • Various reports on bird nests, including the mystery nest, Bald Eagles doing renovations (4:23), and a raven nest John found near his house (5:51). 
  • Elderberry, willow, and aspen trees’ seasonal schedules for breaking bud (9:19) 
  • Alders seasonal color changes (15:05) 
  • A journey through the snow, featuring grouse prints (16:46) and princess pines (18:18) 
  • Coyotes howling at John’s door (19:33) 

That does it for this week! For more phenology, subscribe to our Season Watch Newsletter or visit the Season Watch Facebook page.

Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).

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Charlie Mitchell (she/they) joined the KAXE team in February of 2022. Charlie creates the Season Watch Newsletter, writes segment summaries for the website, and coordinates our Engaging Minnesotans with Phenology project. With a background in wildlife biology, she enjoys learning a little bit about everything, whether it's plants, mushrooms, aquatic invertebrates, or the short-tailed shrew (did you know they can echolocate?).