Invertebrates Archives - Page 15 of 28

April 10, 2014December 31, 2016

Birds and West Nile Virus

It’s that time of year again when we encounter a barrage of public health messages alerting us to take precautions during cold and flu season. However, a different disease outbreak has been making headlines this winter in Utah: West Nile virus.

Though West Nile virus is not a new name to most of us, our familiarity with it typically comes from summer time outbreaks amongst human populations. Yet this particular flare up has gained attention for causing the deaths of over 50 Bald Eagles and it happened during winter.

West Nile virus is maintained in nature by a transmission cycle between mosquitoes and birds. In this cycle, birds simply act as pathogen reservoirs, while the mosquitoes act as pathogen vectors passing the virus on to their eggs and infecting humans and animals through bites. Historically, in the locations of its origin – Africa, Europe, Asia, and the Middle East – this pathogen is rarely fatal to its avian hosts. In fact, antibodies to West Nile virus have been found in the blood of birds native to this region.

It wasn’t until 1997, when a stronger strain of West Nile virus emerged and caused fatalities in a wide range of avian species, that the infection started to be considered pathogenic to birds. When the disease first reached the United States in 1999 it proved to be highly virulent in North American bird populations. The American crow was particularly susceptible. Within 4 months of detection in New York, nearly 5,500 crows died from the infection. Since this first outbreak, West Nile virus spread across the United States and has been isolated in over 250 species of birds, including Bald Eagles.

While wintertime infection amongst human populations is rare, infection during this season is not so uncommon for birds. This is because birds can contract the disease by a variety of routes other than mosquito bites and direct contact. This is especially the case amongst opportunistic scavengers like raptors. If a raptor consumes the carcass of a bird killed by West Nile virus it can contract the virus orally, as the Bald Eagles did after consuming the remains of infected Eared Grebes. Luckily, while bird-to-bird transmission does occur amongst birds that exhibit roosting and group behaviors, the likelihood of a Bald Eagle, which is typically a solitary bird, directly passing the disease to another Bald Eagle is quite low. Meaning that once the last of the infected food source is gone, hopefully no further infections will occur.

For Wild About Utah, I’m Anna Bengtson.

Credits:
Image: Courtesy US FWS
Text: Anna Bengston

Sources & Additional Reading:

World Health Organization. West Nile Virus https://www.who.int/mediacentre/factsheets/fs354/en/
Utah DWR. Wildlife News: DWR Learns What Killed Bald Eagles https://wildlife.utah.gov/wildlife-news/1330-utah-dwr-learns-what-killed-bald-eagles.html

Koenig, W.D., Hochachka, W. M., Zuckerberg, B., and Dickinson, J.L. 2010. Ecological Determinants of American Crow Mortality Due to West Nile Virus During its North American Sweep. Oecologia, 163: 903-909. https://www.nbb.cornell.edu/wkoenig/K156TA_10.pdf

Powell, H. 2010. Counting Crows. BirdScope: Autumn 2010. https://www.allaboutbirds.org/Page.aspx?pid=1956

Rappole, J.H., Derrickson, S.R., and Hubálek, Z. 2000. Perspectives: Migratory Birds and Spread of West Nile Virus in the Western Hemisphere. Emerging Infectious Diseases, Vol. 6, No. 4, July-August 2000, pp. 319-328. https://wwwnc.cdc.gov/eid/article/6/4/pdfs/00-0401.pdf

Reisen, William K. 2013. Ecology of West Nile Virus in North America. Viruses, Vol. 5, Issue 9, pp. 2079-2105. https://www.mdpi.com/1999-4915/5/9/2079

March 20, 2014March 1, 2018

Tick Tock

Hi I’m Holly Strand from the Quinney College of Natural Resources at Utah State University.

It’s springtime–bringing warm light-filled days, colorful blooms, chirping birds and bloodthirsty ticks. Ticks are arachnids like spiders and scorpions. They vary in size, shape, and color. But they all have barbed feeding tubes that they use to excavate a hole in your skin so they can bury their heads and suck your blood. Their accordion-like bodies expand as they sip and sip and sip.

Most ticks go through three life stages after hatching: six-legged larva, eight legged nymph and then adult. The ticks need a single blood meal during each of these life stages. To get this meal, ticks wait for their victims–usually a mammal–using a behavior called “questing.” Questing ticks crawl up the stems of grass or perch on the edges of leaves and extend their front legs–like a toddler signaling he wants to be picked up. The presence of carbon dioxide, or heat, or movement let the tick know that a meal may be passing by soon and the tick gets ready. When a passing animal brushes the tick’s extended legs, the tick simply climbs on board. It doesn’t jump. It just feels and attaches. Some ticks will bore in immediately and others will cruise around looking for a spot where the skin is thin and blood vessels closer to the surface.

This head-burying and blood-sucking behavior alone gives ticks an unsavory reputation. But of course ticks are also dangerous in that they transmit disease through their saliva. The Rocky Mountain wood tick and American dog tick have been found to feed on Utahns. Both can transmit Rocky Mountain spotted fever and tularemia, also known as rabbit fever.

The Western black-legged tick is another Utah native. It’s a vector for lyme disease. According to the Utah Dept of Public Health, it does appear that a small number of individuals may have acquired the disease in Utah. Human transmission from this tick has definitely occurred in California.

Ticks can be found in grasses, shrublands, forests—basically everywhere. Ticks in hotter, arid parts of the state reach peak activity in April and May while ticks at higher elevations are active from May through July. Ticks in all geographic areas are active in the fall as temperatures cool and moisture increases.

Now that I’ve frightened you, know that the chance of getting a tick born disease in Utah is still small. In spite of its name, the vast majority of Rocky Mountain spotted fever cases are reported in eastern and central states. And in any given year there will probably be less than 10 cases of each disease mentioned. And they are all treatable if caught early. So don’t let fear of ticks keep you inside. Just remember that they are out there and check for them when you’ve been brushing up against vegetation.

To remove a tick, do NOT burn it with a hot match or smother it in petroleum jelly. These methods can make a tick burrow deeper before dying. Instead, remove the tick as quickly as possible using the fine tipped tweezers that you carry in your first aid kit.

For more information including tips on tick avoidance and removal go to www.wildaboututah.org.

For Wild About Utah, I’m Holly Strand.

Credits:

Image: Courtesy Bugwood.org, licensed under Creative Commons Attribution 3.0 License.
Text: Holly Strand

Sources & Additional Reading

Centers for Disease Control and Prevention. Pages on Preventing Tick Bites; Life Cycle and Hard Ticks that Spread Disease
https://www.cdc.gov/ticks/avoid/on_people.html [Accessed March 19, 2014]

James, Angela M. 2006. Distribution, Seasonality, and Hosts of the Rocky Mountain Wood Tick in the United States. Journal of Medical Entomology 43(1):17.
https://www.researchgate.net/publication/7272126_Distribution_seasonality_and_hosts_of_the_Rocky_Mountain_wood_tick_in_the_United_States

McDade, J E and V F Newhouse. 1986. Natural History of Rickettsia Rickettsii
Annual Review of Microbiology. Vol. 40: 287-309
https://www.annualreviews.org/doi/abs/10.1146/annurev.mi.40.100186.001443

USU Extension. 2010. Ticks and Associated Diseases Occurring in Utah. Utah Pests News. Volume IV. Summer 2010.
https://utahpests.usu.edu/htm/utah-pests-news/summer2010&ticks

Utah Department of Health, Bureau of Epidemiology.
Fact sheets on Rocky Mountain spotted fever, tularemia and lyme disease.
https://health.utah.gov/epi/fact_sheets/Default.htm

Utah Department of Health, Bureau of Epidemiology.
Historical Communicable Disease Reports 1980 to present.
https://health.utah.gov/epi/100yr/100yr.html

Skerrett, Patrick. 2013. Matchless strategy for tick removal; 6 steps to avoid tick bites. Harvard Medical School Health Blog. Posted June 7, 2013.
https://www.health.harvard.edu/blog/matchless-strategy-for-tick-removal-6-steps-to-avoid-tick-bites-201306076360

Zimmer, Carl. 2013. Outside Magazine, June issue.
https://www.outsideonline.com/outdoor-adventure/science/feeding-frenzy.html

November 14, 2013January 24, 2021

Nature’s Recyclers

Courtesy and copyright Andrea Liberatore, Stokes Nature Center, https://logannature.org/ — Fungi Decomposing Fall
Leaves Outside the
Stokes Nature Center
Courtesy & © 2011 Andrea Liberatore
Stokes Nature Center

Redworms *Eisenia fetida*
from Stokes Nature Center’s
vermicomposting system
Courtesy & © 2011 Andrea Liberatore
Stokes Nature Center

On November 15th, our nation celebrates America Recycles Day. While the day itself tends to focus on human recycling activity, I thought we should also give a nod to nature’s recyclers. Worms, maggots, fungi, beetles, and bacteria – it sounds like a list of leftover Halloween horrors. But in reality, we should be more afraid of what our world would look like without these creepy-crawlies, for these are nature’s recyclers. Scientists call these organisms saprophytes, and as important as their role in life is, they are more likely to evoke a shudder than any feeling of gratitude.

What decomposers actually do is break dead things down into smaller and smaller pieces, until all that is left are the basic molecular components that make up all living things such as nitrogen, phosphorous, carbon, and potassium. Once broken down, this material is then free to be taken up again by plants and animals that use them to live and grow. This cycle of nutrients is vital to life on Earth, and our saprophytic friends make it all possible.

While decomposition would occur even without the help of the decomposers, it would take much, much longer. In some landfills, newspapers have been unearthed that are more than 20 years old, and still quite readable. This is because landfills often create anaerobic environments, where oxygen-loving insects, fungi, and bacteria cannot live and therefore cannot aid decomposition. If without decomposers, a newspaper can last 20 years, what would happen to much larger and hardier items such as tree trunks and roadkill? I shudder to think about it.

Did you know that the U.S. throws more than 33 million tons of food waste into landfills each year? This organic material goes to waste there – taking up valuable space and taking longer than normal break down. So this year, celebrate America Recycles Day by employing some of nature’s recyclers in your yard. Consider starting a compost pile where your fall leaves and food scraps can get broken down into nutrient-rich all-natural fertilizer for next year’s garden.

For composting tips and more information about nature’s recyclers, visit Wild About Utah online at www.wildaboututah.org. Thank you to the Rocky Mountain Power Foundation for the research and development of this Wild About Utah topic. For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

Credits:

Photos: Courtesy & © 2011 Andrea Liberatore, https://logannature.org/
Text: Andrea Liberatore, Stokes Nature Center, logannature.org

Composting Tips & Information:

Farrell-Poe, K. and Koenig, R. (2010) Backyard Composting in Utah. Utah State University Cooperative Extension. https://extension.usu.edu/files/publications/factsheet/HG-Compost-01.pdf

U.S. Environmental Protection Agency: Composting. https://www.epa.gov/epawaste/conserve/rrr/composting/index.htm

Additional Reading:

Fogel, R. (2002) Waste Not, Want Not: Fungi as Decomposers. Utah State University Herbarium. https://utahpests.usu.edu/ipm/ornamental-pest-guide/diseases/wood-decay-fungi

Hoff, M. (2009) Young Naturalists: Nature’s Recyclers. Minnesota Conservation Volunteer Newsletter. July-August 2009. https://files.dnr.state.mn.us/publications/volunteer/young_naturalists/natures_recyclers/natures_recyclers.pdf

U.S. Environmental Protection Agency (2011) Basic Information About Food Waste. https://www.epa.gov/osw/conserve/materials/organics/food/fd-basic.htm

October 31, 2013December 4, 2023

Shrikes

Loggerhead Shrike
*Lanius ludovicianus*
Copyright 2013 Linda Kervin

Northern Shrike
Lanius borealis
Courtesy US FWS, Dave Menke, Photographer

Northern Shrike Courtesy US FWS, Dave Menke, Photographer — Loggerhead Shrike
*Lanius ludovicianus*
Copyright 2013 Linda Kervin

Northern Shrike
Lanius borealis
Courtesy US FWS, Dave Menke, Photographer

The name songbird conjures up an image of a colorful singing warbler. But one family of songbirds, the shrikes, are fierce little predators. No bigger than a robin, shrikes mainly eat insects, especially grasshoppers and crickets, but they also prey on rodents, small birds, lizards, snakes and frogs.

Utah has 2 species of Shrike: the Loggerhead which resides here year round and the Northern which breeds in tundra and visits Utah in the winter. Shrikes prefer semi-open country that has some trees, shrubs or fenceposts where they perch to watch for prey and then swoop to kill with their thick hooked bill.

Shrikes are sometimes called butcher birds Continue reading “Shrikes”