ARBORETUM NEWS (NATURALISTSNOTES)

EARLY MIGRANTS

SUNDAY, MARCH 31, 2013

Mother Nature lied to us on Easter Sunday. At 1:00 she promised us a lovely, sunny afternoon – but she failed to deliver. Standing on the Visitor Center steps for the introduction to our tour, we reveled in warm sunshine on our faces, but by the time an hour and a half had passed, we were chilly and wondering if the gray clouds which now dominated the sky were going to send us snow.

They didn’t – and actually, we had a really wonderful tour despite the meteorological downturn. We began with a flyby of sandhill cranes! Before my preliminaries were finished, we heard that unmistakable rattling call, and very soon a pair of cranes emerged from somewhere south of us, passing nearly directly overhead. What a moment!

Like many other creatures at this time of year, cranes are partnering up and evaluating homesites. Sunday’s pair was probably the same one we’ve been seeing in the Arboretum for a week or two. It was a thrilling start for our hike.

My topic was ‘Early Migrant Birds’, and my two best pieces of news in that regard had to do with woodcocks and bluebirds. Both had returned to the Arboretum late that same week from their wintering grounds – the southeastern United States and Texas/Mexico respectively.

You’ll have to come on a night hike, or visit the Arboretum at dusk on your own, to see and hear woodcocks. But the bluebirds showed themselves off to us wonderfully on Sunday!

We spotted a male/female pair in the Native Plants Garden, near the woodland garden area. They swooped up and down between the ground and low tree branches several times, affording everyone a fine view.

bluebirds

Their color differences were obvious in the good light: the male is much brighter blue and orange, while the female is brownish with touches of blue, especially on her tail. The coloring on her breast is paler as well. This couple seems to be investigating the bluebird nesting boxes nearby, which were just inspected and cleaned a few days ago. Let the bluebird season begin.

Our next encounter was with red-tailed hawks. There is a brand-new nest not far from the Visitor Center, which I had learned about on Thursday morning. I took the large crowd of visitors to see it, keeping what I hoped was a respectful distance.

The nest is fairly well concealed in a tall white pine tree. You may notice grassy nesting material dangling down, particularly when it moves in the wind.

From our vantage point we couldn’t really tell if there was a bird on the nest or not.

redtail by Michael Leland

But suddenly we DID know – because the mate came flying in, landing gear down and tail feathers flared! The two birds quickly traded places and the one which had been sitting on the nest flew off, presumably in search of food.

Since the hawks are keeping so closely on the nest, I surmise that they have a clutch of eggs laid already. Red-tails have an extremely wide home range – from the Caribbean to Alaska – and suit the timing of their breeding to their locale. In warmer areas, they may breed in January; in the interior of Alaska, they wait until late May. Frankly I think this couple might be rushing things a bit in having eggs in the nest in March, but hopefully they know what they are doing.
I confess to a special fondness for red-tailed hawks. The sight and sound of them will never get old for me, especially that aerial scream – Keeeeeer! It seems to dissolve something in my spine every time I hear it, no matter how many times it’s been.

Finally tearing ourselves away from the hawks’ place of residence, we went to see a few flowers! Really! There are a couple of shrubs in Longenecker Gardens which are already in bloom.

One of them is vernal (spring) witch hazel.

Vernal witch hazel

No, the flowers are not as showy as hybrid tea roses; but they do provide a spot of color against the dull tones of March. The garden’s collection includes yellow, purple, and red-flowering varieties.

Regular readers of NewsLeaf (the monthly publication of the Friends of the Arboretum) may recall articles about autumnal witch hazel – a brave plant which flowers in November and even December. What we have now is the spring-flowering equivalent. Either way, witch hazel is in bloom when very little else is. Use a magnifying glass, or flip your binoculars upside down, for a detailed look at the flowers’ structure.

We then ventured across the slush and mud to the pussywillow collection.

pussywillow catkin

Yes, those are flowers, too – a particular type called a catkin. Catkins are long, slender clusters with no obvious petals. (Think of a miniature ear of corn, and you’ll have the image about right.) Other catkin-forming trees and shrubs include birches, alders, poplars, mulberries, oaks, and hazelnuts.

Catkin flowers are usually unisexual. In some cases only the male flowers occur in catkin form; on pussywillows, both sexes do. The pussywillows which are in bloom now are males.

I’ve given this mini-lecture before: there are a couple of different ways plants can divide up the boy parts and the girl parts. Pollen from the former has to reach the reproductive tissues of the latter in order for seeds to form. Monoecious plants have separate male and female flowers, but both occur on the same plant; dioecious plants also have separate male and female flowers, but each individual plant only has flowers of one or the other gender. This is the case with all of the willows – there are girl trees and boy trees.

There’s a third way, which is the route followed by most ornamental species: to contain both male and female structures within each flower. What do we call those? We call them PERFECT. I am not making that up.

We took a final detour over to the tamarack and larch collection before concluding our tour. The group numbers were down a bit at that point due to a chilly wind and forbidding skies.

I find these trees fascinating, a sort of biological missing link. I’ve been known to call them “evergreens that aren’t”. They’re definitely conifers – bearing their seeds in cones, and wearing needles rather than broad leaves – but every fall, those needles turn yellow and fall off, leaving the tree bare for the winter. I wanted to see if the tiny bunches of new needles were in evidence yet. News flash: they aren’t. But keep looking! They will be soon!

We’re weary of winter by now … so nice to search for, and find, evidence of life continuing in the plant and animal world. Here comes April, the morning of the year.

Kathy Miner, Arboretum naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.