by Jeff Stehm
In early November, I had the special pleasure of spending a few hours in the British Natural History Museum. Similar to the Smithsonian Natural History Museum, a few hours does not do it justice, but I had a plane to catch. Below is a slide show of photos I took as I ran through the museum and a video at the end. Hope you enjoy them.
Seeing a ton of acorns on the ground? It must be a ‘mast’ year for oaks.
By Emily Moran, Washington Post 11.26.19
(submitted by Charlene Uhl, Class X)
If you have oak trees in your neighborhood, perhaps you’ve noticed that some years the ground is carpeted with their acorns, and some years there are hardly any. Biologists call this pattern, in which all the oak trees for miles around make either lots of acorns or almost none, “masting.”
In New England, naturalists have declared this fall a mast year for oaks: All the trees are making tons of acorns all at the same time. Many other types of trees, from familiar North American species such as pines and hickories to the massive dipterocarps of Southeast Asian rainforests, show similar synchronization in seed production. But why and how do trees do it?
Every seed contains a packet of energy-rich starch to feed the baby tree that lies dormant inside. This makes them a tasty prize for all sorts of animals, from beetles to squirrels to wild boar.
If trees coordinate their seed production, these seed-eating animals are likely to get full long before they eat all the seeds produced in a mast year, leaving the rest to sprout.
For trees like oaks that depend on having their seeds carried away from the parent tree and buried by animals like squirrels, a mast year has an extra benefit. When there are lots of nuts, squirrels bury more of them instead of eating them immediately, spreading oaks across the landscape.
Getting in sync
It’s still something of a mystery how trees synchronize their seed production to get these benefits, but several elements seem to be important. First, producing a big crop of seeds takes a lot of energy. Trees make their food through photosynthesis: using energy from the sun to turn carbon dioxide into sugars and starch. There’s only so many resources to go around, though. Once trees make a big batch of seeds, they may need to switch back to making new leaves and wood for a while, or take a year or two to replenish stored starches, before another mast.
But how do individual trees decide when that mast year should be? Weather appears to be important, especially spring weather. If there’s a cold snap that freezes the flowers of the tree — and yes, oaks do have flowers, they’re just extremely small — then the tree cannot produce many seeds the following fall.
A drought in the summer could also kill developing seeds. Trees will often shut the pores in their leaves to save water, which also reduces their ability to take in carbon dioxide for photosynthesis.
Because all the trees within a local area are experiencing essentially the same weather, these environmental cues can help coordinate their seed production, acting like a reset button they’ve all pushed at the same time.
A third intriguing possibility that researchers are still investigating is that trees are “talking” to one another via chemical signals. Scientists know that when a plant is damaged by insects, it often releases chemicals into the air that signal to its other branches and to neighboring plants that they should turn on their defenses. Similar signals could potentially help trees coordinate seed production.
Investigation of tree-to-tree communication is still in its infancy, however. For instance, ecologists recently found that chemicals released from the roots of the leafy vegetable mizuna can affect the flowering time of neighboring plants. While this sort of communication is unlikely to account for the rough synchronization of seed production over dozens or even hundreds of miles, it could be important for syncing up a local area.
Masting and the food web
Whatever the causes, masting has consequences that flow up and down the food chain. For instance, rodent populations often boom in response to high seed production. This in turn results in more food for rodent-eating predators such as hawks and foxes; lower nesting success for songbirds, if rodents eat their eggs; and potentially higher risk of transmission of diseases such as hantavirus to people. If the low seed year that follows causes the rodent population to collapse, the effects are reversed.
The seeds of masting trees have also historically been important for feeding human populations, either directly or as food for livestock. Acorns were a staple in the diet of Native Americans in California, with families carefully tending particular oaks and storing the nuts for winter. In Spain, the most prized form of ham still comes from pigs that roam through the oak forests, eating up to 20 pounds of acorns each day.
So the next time you take an autumn walk, check out the ground under your local oak tree — you might just see the evidence of this amazing process.
Emily Moran is assistant professor of Life and Environmental Sciences at the University of California at Merced. This report was originally published on theconversation.com.
Washington Post 11.26.19
by Jeff Stehm
I just watched a webinar on a fantastic new macroinvertebrate identification and citizen science training site – Macroinvertebrates.org! This site, developed under a National Science Foundation grant, took 3-years to bring to life through the efforts of a multi-disciplinary team of scientists and educators. Over 150 macroinvertebrate species of the eastern United States are listed on the site. Identification is facilitated by the over 800,000 high-resolution and expandable images taken of each species as well as the expert content and annotations developed, including key identification features and pollution sensitivity.
The website development involved a set of partner organizations that helped define identification problems and needs, tested the website design and functionality, and participated in research on how citizen scientists learn observational identification tasks. The website has about 5,000 visits a month and surveys indicate that over 90 percent of trainees and trainers come away with greater confidence and accuracy in their identification capabilities and teaching methods.
The website is packed with information, various stunning and expandable views of each organism, printable resources, including a training manual and identification sheets, an informative blog, and other resources. So, check it out! Fantastic and a must see! www.macroinvertebrates.org. Click here for website quick start guide.
For the more ambitious, check out the Taxonomic Certification Program
of the Society for Freshwater Science at https://stroudcenter.org/sfstcp/
By Jeff Stehm
As November arrives it is time to pull out our binoculars and cameras and go gawk at the gobblers, otherwise known as Meleagria gallopavo silvestris or the eastern wild turkey. With some luck, a little study, and observation (and a judicious reading of this blog) you’ll be able to wow your Thanksgiving Day guests!
Range, Habitat and Food
Wild turkeys currently exist in 49 states (yes, Hawaii; no Alaska), southern Canada and Mexico. They have historically ranged throughout North America. However, by the early 20th century, hunting and habitat destruction had reduced the population to about 30,000. Conservation efforts in the 1950s and 1960s brought the current population back to about 6-7 million, although in some states (Mississippi and Arkansas) their numbers are declining because of habitat loss. In Virginia, wild turkeys number about 180,000 to 200,000 with the higher concentrations found in the Tidewater, South Mountain, and South Piedmont regions.
Source: Wikipedia Source: VA DGIF
The home range of individual birds in the spring can be as much as 3 – 4 square miles, shrinking to as little as 50 acres in the winter. In terms of habitat, wild turkeys prefer hardwood and mixed conifer-hardwood forest with areas of pasture, fields, orchards, and seasonal marshes. Of course our beloved Blue Hills fit this bill. Planting nut and berry trees is a good way to encourage turkey populations as well as practices such as prescribed burning, forest thinning, and grazing. One of the reasons for their extensive range in North America is the wild turkey’s opportunistic foraging. Wild turkeys are omnivores. While they prefer acorns, nuts and other hard seeds, they also eat berries, roots, insects, and the occasional amphibian, small reptile and small snake. This ability to feed on a range of food sources allows wild turkeys to survive in different areas of the country.
Characteristics and Life History
Turkey communities consist of toms (adult males), jakes (juvenile males), hens (females) and poults (young chicks). Toms weigh from 17-21 pounds and 40 inches tall, and hens weigh 8-11 pounds and 30 inches tall.
A Jake in Pennsylvania, Source: US FWS (Photo: Bill Buchanan/USFWS)
An interesting anatomical feature of the toms is the snood – an adornment that dangles from between the eyes. The snood can change color and length based on the tom’s excitement. Turkeys walk a lot and are not known for their flight ability, but they can fly up to 55 mph in short bursts and can run at 18 mph. At night, turkeys will fly into trees to spend the night as protection from predators.
Turkeys have acute eyesight and hearing, but poor taste and smell. Turkeys’ eyes are located on the sides of their head, giving them monocular vision. They compensate by turning their heads to better judge distance. This is combined with excellent hearing allowing turkeys to locate the source of a sound with uncanny ability. Field studies suggest turkeys hear at lower frequencies and can hear more distant sounds than humans. Turkeys’ key defense against predators, therefore, is their sight and hearing. In sum, don’t move when a turkey is looking and don’t think about moving when they’re not.
At times, turkeys can also be aggressive in self-defense against predators, if cornered, or if defending territory.
Mating and Nesting. Mating season is March to June and nesting occurs from mid-April to mid-June. Nesting sites are on the ground, typically in native bunchgrasses, forbs, or shrubs between 20-26 inches tall. Nests are a shallow depression or bowl scratched out from the dirt. Hens lay between 9-13 eggs over a two-week period. Incubation takes about 28 days. Poults take about two weeks before they are able to fly up into trees for protection, and hence are vulnerable to predation during this early period.
Survival Rates and Predators. Studies indicate that only 10 to 50 percent of nests successfully hatch and then only about 25-50 percent of poults will make it beyond 4 weeks. Most of this loss is due to predators such as foxes, skunks, raccoons, possums, crows, hawks, and some snakes.
Fun Facts about Wild Turkeys
Hope you enjoyed this brief romp through gobbler land!
VA Department of Games and Inland Fisheries https://www.dgif.virginia.gov/wildlife/turkey/
Wild Turkey – Wikipedia https://en.wikipedia.org/wiki/Wild_turkey
Wild Turkey Life History, Cornell Ornithology Lab www.allaboutbirds.org/guide/Wild_Turkey/lifehistory
Eastern Wild Turkey https://wildlife.tamu.edu/wildlifemanagement/eastern-wild-turkey
National Wild Turkey Federation www.nwtf.org
Wild Turkeys https://thevlm.org/portfolio_page/wild-turkeys/
How to Draw a Turkey http://paolosaporiti.com/how-to-draw-a-turkey-step-by-step/
by Bonnie Beers
During my career as a special educator, I worked with groups of students for whom time was at a premium. As we moved through lessons and activities, I often found myself asking what I call the ‘So What?’ questions. So What? Is this lesson worth their time? Why does this skill matter? Does it expand their educational, vocational, or personal pathways? What steps need to happen to make a skill more than an addition to a bag of tricks?
Reading through the blog entries about recent studies that document alarming bird population declines over the past 30 years, I find myself thinking that this research answers the ‘So What’ questions regarding Citizen Science. Many times, Citizen Science may feel like a fun field trip--a day in the woods listening and looking; observing birds, butterflies, or other wildlife; noticing and documenting plants; pulling invasives; counting invertebrates in a stream. The Cornell study, Link to Science Magazine article, demonstrates that the data we collect combines with data across the country and world to provide information that cannot be generated in any other way. The NEXTAR radar provided important facts about the decline in overall avian biomass over the past 30 years. Citizen Science data over time, however, documented specific species losses, and gains. The study demonstrates that policies protecting species and ecosystems have made a difference in targeted populations of birds. The patterns lead to understanding the effects of some factors we cannot control, but also of some that we can influence.
As ORMN members, we have some opportunities coming up:
Cornell Feederwatch: begins November 9
Sign up to sit at home with the beverage of your choice and document the birds that you see at your feeder. The requirement is to spend 2 consecutive days watching for whatever amount of time you can or desire, not necessarily contiguous. You can watch 2 days weekly or less often, whatever fits your time. Report your data on paper or online to Cornell.
Sign up at : https://feederwatch.org/
Christmas Bird Watch: December 14.
Join a team of ORMN members to spend a day looking and listening for birds at your assigned site. Good company (both birds and people!).
Contact Victoria Fortuna if you are interested in joining a team. (Audubon Project)
Audubon is launching a new Citizen Science project in 2020 to understand effects of climate changes by surveying populations of specific bird species: bluebird, nuthatch, painted bunting, goldfinch, and towhee. When you sign up, you identify an observation site and follow procedures to survey your selected species on one day between January 15- February 15, and one day between May 15 and June 15.
For more information: https://www.audubon.org/features/esri-climate-watch
Topic suggested by Barry Buschow
Alabama Cooperative Extension System describes Japanese stilt grass (Microstegium vimineum) as an aggressive invader of forestlands throughout the eastern United States. Boy is that an understatement! If my small plot of woodlands is any example, stilt grass is a never-ending juggernaut. But as the map below shows, I’m not alone in the Eastern United States in having stilt grass.
The plant was accidentally introduced into the Tennessee around 1919 as a result of being used as a packing material in shipments of porcelain from China.
Stilt grass is considered one of the most damaging invasive plant species in the United States. It is well adapted to low-light levels. Infestations spread rapidly with flowering and seed production in late summer. The seed can remain viable in the soil for up to five years.
Infestations also impact the diversity of native species, reduce wildlife habitat, and disrupt important ecosystem functions. In particular, stilt grass can reduce growth and flowering of native species, suppress native plant communities, alter and suppress insect communities, slow plant succession and alter nutrient cycling. However, it does serve as a host plant for some native satyr butterflies, such as the Carolina Satyr Hermeuptychia sosybius and the endangered Mitchell's Satyr Neonympha mitchellii (Wikipedia).
Correct identification is necessary before beginning any management activities. Fortunately, Japanese stilt grass has a unique combination of characteristics that make field identification possible. A field guide published by the Alabama Cooperative Extension System provides simple descriptions and clear pictures of these characteristics along with details on how to distinguish several common look-a-like species.
Since Japanese stilt grass is an annual grass, the primary goal is to prevent it from producing seeds. Management techniques include hand pulling, mowing, spraying, burning, goats, and biological control. The New York Botanical Garden's website provides some simple tips on controlling stilt grass. However, choosing the right combination of control methods, applied at the right time, is important so as not to further damage the environment or ecosystem.
For instance, the widespread use of herbicides has greatly contributed to wiping out native milkweed plants contibuting to the 80 percent decrease in monarch butterflies in the past 20 years. Everything has trade-offs.
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ORMN Class IX