There is no glory in star or blossom till looked upon by a loving eye;
There is no fragrance in April breezes till breathed with joy as they wander by.
— William C. Bryant
Using my ECOlogical Calendar as a guide, here’s what’s happening this week in nature.
Map of the Spring sky:
When we look into the sky on spring nights, we are looking away from the center of our galaxy, the Milky Way. Consequently, we see fewer stars and have a less-obstructed view outward beyond our galaxy’s confines. The map above shows where to find northern hemisphere constellations during the spring months.
The bright star to look for this week is Rasalhague (apparent magnitude 2.08) in the constellation Ophiuchus the Serpent Bearer. Rasalhague is the brightest star of this large and dim constellation, which has the shape of a simple house. In April, you can find this constellation in the east along the horizon with Rasalhague pointing towards the north.
The bright blue spring sky prompts the classic question among children: “Why is the sky blue?” We’ve all heard the question, and most of us by now know the answer: Gas molecules and dust particles in the Earth’s atmosphere scatter blue light more than other colors in the spectrum; thus the sky’s predominant color.
Butterflies are on the move! Once outdoor temperatures consistently start reaching 60 degrees Fahrenheit (16 degrees Celsius), butterflies will begin flying. For us insect lovers, it will soon be time to catch, study, and release — just for fun! Ever wonder why your fingers seem dusty after handling a butterfly? Butterfly wings are covered with colorful scales of dust. The scales come off easily and helps them escape from spiders’ webs.
Here is the same butterfly species (peacock swallowtail) with the scales rubbed off throughout parts of its wings.
Allergy season is here, and did you know it’s worse in the morning? As the sun rises, temperatures rise, creating winds that disperse pollen. Airborne pollen concentrations are usually highest in the morning.
In early spring, sandhill cranes begin the migration to their breeding grounds. Throughout the spring, the cranes can be seen resting and feeding along rivers and wetlands throughout the Great Plains and Pacific Northwest. The largest congregation of sandhill cranes occurs from February to early April along the Platte River in Nebraska. Sandhill cranes are monogamous — they pair bond for life — and raise only one brood annually.
Springtime growth thrives on water supplies unlocked as temperatures rise. The increase in temperature causes more evaporation, further increasing snowmelt. Some places in the north say they have five seasons. Between winter and spring is the season of “mud.”
About “This Week in Nature”
To illustrate the widest range of natural events, I depict the seasonal activities found in the Northern Hemisphere, and I have chosen to present the most intense expressions of each season. My “This Week in Nature” posts are not meant to be specific to any one geographical area. They are intended to evoke the essence of the seasons and to emphasize the cycles of nature. The goal is to simply offer a glimpse of the natural phenomena that make each day an amazing event.