The weather pulled a quick switcheroo on us this week, bringing heavy snowfall and cold weather to a region that was already moving quickly into spring. Lakes, which had just shed their winter ice, quickly refroze to some extent. Emerging buds froze on their branches, and migrating birds either hunkered down uncomfortably or turned tail and flew south.
All this has thrown John’s records into disarray: he’s never seen Crooked Lake refreeze after the spring thaw. What should his records show: The first ice-out date, or date that ice disappeared for the season?
John’s migration records pose a similar problem. John saw his first American Robin of the year on March 12, the earliest arrival on record by 4 days. However, they’ve since disappeared. Does the record stand? Or should John mark the first migratory robin that stays as the first of the year?
These are thorny problems that I’m happy to leave to the experts. While they puzzle over that, I’ll be over here getting relaxation advice from the real experts: chipmunks! (Read more below.)
Timestamps
- Introduction (0:00-0:29)
- Ice out, ice in, ice out again? (0:29-3:18, 5:45-6:27)
- John’s written notes for the week (3:18-4:04)
- Migrating birds (4:04-5:45, 11:54-12:51)
- Robins and Red-winged Blackbirds (4:04-5:45)
- Redpolls and juncos (11:54-12:51)
- Earliest spring ever! Or not? (4:53-6:27)
- A strange time for sundogs (6:27-7:30)
- Precipitation report (7:30-8:26)
- Plant development (8:26-10:47)
- Red elderberry, silver maple, speckled alder (8:26-9:29)
- Hazel (9:29-10:21)
- Aspen (10:21-10:47)
- Chipmunks emerging (10:47-11:29)
- Bird feeder visitors (11:29-12:51)
- Trumpeter swans in snow (12:51-13:21)
- Nesting eagle update (13:21-14:21)
- Conclusion (14:21-15:00)
Chilled-out chipmunks
John saw his first chipmunk of the year last week, 3 days earlier than his average first sighting. Chipmunks don’t live off stored body fat all winter; instead, they periodically wake up to snack on their stored food, then head back to a heavy sleep called torpor.
In spring, chipmunks wake up more frequently, potentially to check out the weather. Early-rising chipmunks have a head start on the energetically demanding spring mating season, but this comes at a risk: if they get up before food is available aboveground, they can burn through the last of their winter stores quickly.
A chipmunk with a well-stocked larder, however, can have the best of both worlds. This lucky rodent can wake up bright and early, get their reproductive organs firing, and eat a hearty breakfast no matter what the conditions are like outdoors. What a way to start the new year!
Mast-ers of relaxation
A chipmunk’s winter food cache is mostly made up of nuts and seeds. However, the supply of these foods vary from year to year. Many trees, such as oaks, maples, and hazels, have mast and non-mast years. Mast years are characterized by a huge abundance of seeds and nuts, while non-mast years provide chipmunks with next to no food.
This tactic works well for the trees, since some of their seeds inevitably get missed or forgotten in the super-abundant mast years and are left to become new trees. During non-mast years, the trees are able to store energy and recover for the next season.
Chipmunks deal with this fluctuating food supply in some fascinating ways. One study found that chipmunks just don’t bother foraging in autumns without a large seed crop, instead heading to hibernation early and living off their stores from previous years. A well-provisioned chipmunk can survive from 9-11 months on stored food alone!
To double-check, the researchers attached radio transmitters to the chipmunks in spring and checked their locations in an autumn without a mast crop. Sure enough, many chipmunks were found nestled in their burrows, living happily off the seeds of a previous year’s crop.
It seemed unlikely to me that chipmunks would be able to store nearly two winters’ worth of food from what they could gather from one year’s mast crop. However, I was wrong: researchers tracked the foraging and caching success of chipmunks during a red oak mast year, and they found that chipmunks could gather enough acorns to survive the winter in just one to two days’ effort.
So, what can we learn from our furry little rodent friends? Reap the harvest in good years, and don’t wear yourself ragged during the bad ones.
Take a nap, eat a snack, and wait for the good times to come again!
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).
