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Observations by Gary Fewless for Green Bay WI (Lat.N 44.51° Long. W 88.02° ), except as noted. For flowers lacking conspicuous petals or sepals I define "anthesis" as release of pollen by mature anthers.

April 2010april green-up

Mouse-over the photo for the identity of the subject

April 30

April, like March, was an unusually warm month. Green Bay's average temperature was 6.1° F above average. That makes it the second warmest April on record. Today Green Bay received 0.29 inches of rain, which seemed like a lot more judging by how long of a period it covered.

First day of flower for Geranium maculatum (wild geranium).

April 29 Rubus pubescens (dwarf red raspberry) is in flower.
April 28

The morning low was 32° F in Green Bay and a very cool 24° in Rhinelander about 100 miles NW.

Ribes missouriensis (missouri gooseberry) is in flower.

Red Admirals (Vanessa atalanta) have been flying around in yard, Hofa park, Seymour, Outagamie County (Elaine Olsen Friedrick).

April 27 A morning low of 37° F in Green Bay and widespread frost and freezing farther north. Rhinelander reported 30°.
April 26

The morning low temperature fell to 39° F as a mass of colder air moves in, but the temperature rose to 61° in the afternoon.

Thalictrum dioicum (early meadow rue) in flower (anthesis).

April 25

Green Bay received 1.19 inches of much-needed rain.

Ribes americanum (American black currant) is in flower, City of Green Bay in woods.

April 23 Prunus virginiana (choke cherry) flowering, and I saw a House Wren darting about, City of Green Bay (Brian Pierce).
April 22

Prunus americana (American wild plum) and Ostrya virginiana (ironwood; hop hornbeam) in flower, UW-Green Bay. I haven't had time to derive the precise numbers, but many phenology items are "off the charts" early compared to my data for the last 25 years or so. Some phenology items have been 7-10 days earlier than the previous earliest date in 25 years!! That is not surprizing because March in Green Bay was about 6 degrees F warmer than the average and April is running about 10 degrees warmer than average. Those are huge departures.

First open flowers in a few Trillium grandiflorum (trillium), City of Green Bay.

Barn Swallows arrived in the evening, City of Green Bay .

April 21 Asarum canadens (wild ginger) in flower, City of Green Bay, in woods.
April 20 Sambucus pubens (red elderberry) flowering, Green Bay.
April 18

Spring azure butterfly on UW-Green Bay's Cofrin Arboretum. They have probably been out before now, but this is the first I've seen.

Viola sororia (common blue violet) and Amelanchier arborea (juneberry) in flower as well as the alien weeds Senecio vulgaris (sticky ragwort) and Lamium amplexicaule (henbit)

April 17

Fraxinus pennsylvanica (green ash), Anemone quinquefolia (wood anemone) and Viola pubescens (yellow violet) are all in flower.

The weedy Veronica arvensis (corn speedwell) and Veronica peregrina (bird's-eye speedwell) are in flower, UWGB.

April 16

Acer saccharum (sugar maple) and Betula papyrifera (paper birch) in flower, UWGB.

Viola labradorica (dog violet; previously known as Viola conspersa) in flower.

The alien and invasive plant Euphorbia cyparissias (cypress spurge) is in flower, City of Green bay.

April 15

I saw an adult Snapping Turtle crossing the road (Circle Drive) on the UWGB campus today. Possibly recently out of winter quarters and looking for a mate.

Blue-gray gnatcatcher, ruby-crowned kinglet, many yellow-rumped warblers, American Toads in full chorus Three pairs of mating Green Darners and one Variegated Meadowhawk(Sympetrum corruptum), Green Bay ( Joan S. Berkopec).

American toads "singing" in Allouez too, Brown County.

April 14

Mostly sunny and a high temperature of 72° F.

Cardamine diphylla (toothwort; previously known as Dentaria diphylla) in flower.

April 13 Cardamine douglassii (purple spring-cress) in flower.
April 11

Sturgeon have begun to spawn in the Wolf River. [in full spawning mode by April 12, gf; photo from a previous year]

Suckers (fish) in Mahon Creek on UWGB's Cofrin Arboretum.

April 10

Carex pensylvanica (Pennsylvania sedge) in flower (anthesis), UWGB. That is 5 days earlier than the earliest I had recorded since 1986.

First day of flower for Cardamine concatenata (cut-leaved toothwort), UWGB. That is 2 days earlier than the earliest previous observation. Also a few open flowers for Barbarea vulgaris (yellow rocket) on UWGB. That is 7 days earlier than the previous earliest date (23 years data).

Cabbage butterfly flying on UWGB. That is 8 days earlier that the previous earliest, with16 years of data.

April 9

Acer negundo (box elder) in flower (anthesis) at UWGB and widely in the Green Bay area. That is 4 days earlier than the earliest I have observed over the previous 24 years.

First flowering for Claytonia virginca (spring beauty) on UWGB campus.

April 8

Snowfall amounts varied considerably in northeastern Wisconsin, but some areas got at least 5 inches, as we did in Allouez. It's easy snow to measure too, because it is heavy and wet and doesn't blow around. The National Weather Service weather station recorded 5.8 inches of snow for the storm extending from late on April 7 through April 8. Here's a photo of the snowy conditions at about 8 a.m. in Allouez. What a difference a day can make. Rhinelander 100 miles NW had no snow. Oshkosh about 60 miles south also had no snow.

White Pelican soaring over the mouth of the Fox River this afternoon, City of Green Bay (Brian Pierce).

April 7 More rain, turning to snow in the evening.
April 6 Green Bay received 1.22 inches of much-needed rain today. More rain and maybe snow is forecast for tomorrow.
April 5

First Day of flower for Medicago lupulina (black medick), another alien weed of disturbed sunny sites.

First open flowers of Erythronium albidum (white trout lily), City of Green Bay, Red Smith Park area (Amy Wolf).

I don't know how long the bats have been active, or even what species I saw, but they were out tonight when I walked my dog late, near the East River in Allouez.

We received a little rain today (Green Bay had 0.17 inches). More rain is forecast, and even snow has been mentioned for our future.

April 4

First day for release of spores by Equisetum arvense (common horsetail)and first day of flower for Thlaspi arvense (field pennycress), a common alien weed of disturbed sunny sites. This flowering date for Thlaspi arvense is 10 days earlier than the previous earliest record in my records and the average for 23 years of data (1986 through 2010, lacking 1997 and 2000) is April 29.

New migrants here today included golden-crowned kinglet and chipping sparrow; first open flowers on (Claytonia
) spring beauty, Town of Cooperstown, Manitowoc County, Wisconsin (Joel Trick).

April 3

First day of flower (anthesis) for Juniperus chinensis (Chinese juniper) and Taxus cuspitata (Japanese yew), both horticultural plantings on the UW-Green Bay campus.

First day of flower (anthesis) for Thuja occidentalis (white cedar) and Populus grandidentata (big-tooth aspen), both native species on the UW-Green Bay campus.

First observation of Yellow-rumped Warbler, Town of Cooperstown, Manitowoc County, Wisconsin (Joel Trick).

April 2

Tree swallows have returned, Oconto County, Pensaukee (Tom Erdman).

First day of fully open flowers for Taraxacum officinale (dandelion), UW-Green Bay and various other sites in City of Green Bay.

April 1

First day of flower (anthesis) for Acer rubrum (red maple), UWGB and elsewhere in City of Green Bay. That is the earliest flowering date for this same tree, with 23 years of data, and it is 9 days earlier than the previous earliest date! The average date of first flower has been 04/18. If this very warm weather continues we can expect to see more records broken.

The high temperature in Green Bay was 75° F! The average ("normal") high temperature for this date is 47°. Very dry conditions continue.

The photo at the top of this page illustrates the green-up of April 2009 (last year) in forest on UW-Green Bay's Cofrin Arboretum. Here is a similar paired photo in lawn near the UWGB soccer fields.

New arrivals here today included Eastern Phoebe, Tree Swallow and Yellow-bellied Sapsucker, Town of Cooperstown, Manitowoc County, Wisconsin (Joel Trick).

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Last updated on May 20, 2015