Some of you may be old enough to remember the widely reported stories published in the late 1980s and early 1990s about the conflicts between the logging industry and those advocating for the Northern Spotted Owls (Strix occidentalis caurina).  

Northern Spotted Owl
Northern Spotted Owl © Mark Sheehan | Dreamstime.com

Conservationists stated that logging destroyed critical habitats, endangering the owls.  The owls under threat were also recognized as an indicator species for many others in the old-growth forests of the Pacific Northwest. Loggers believed that the research regarding the needs of these owls was flawed. They further stated that the conservationists’ arguments needlessly threatened thousands of jobs. The battle continued for years and in many venues.  Ultimately, a judge ordered the Forest Service to revise its operations “to ensure the northern spotted owl’s viability.”  That occurred in 1992.

During the almost 30 years since the ruling and despite changes to logging practices, the number of Northern Spotted Owls continued to decline, especially during the most recent 10 years.  However, there is sort of good news.

A study published earlier this summer by multiple government agencies along with university research teams offered another aspect to the saga of the struggling owl species.   The report discussed the impact of a Barred Owl (Strix varia) population swell within the habitat during a 17-year study.  Barred Owls are considered invasive in this area and are fierce competitors for food and space use.  

To test a hypothesis, the research team enacted a pilot program to remove the invasive barred owls within two locations that were also under the forest conservation effort.  The program was conducted between 2009 and 2013.  Within these areas, the spotted owl population decline was only 0.2% per year as compared to a loss of 12.1% per year in areas without intervention.   

The influence of the barred owls on the habitat was not limited to the spotted owls.   As an overabundant species, it may also have negatively impacted other forest species. Consequently, they may have rebounded although they were not monitored.

The removal of the barred owls sparked its own controversy.   Not only is the suppression program costly and difficult to implement but the owls were euthanized.  This is a sad solution.

The argument then circles back to the need to protect and preserve more old-growth forests so that the species can reclaim a balance, hopefully without a plan that involves more killing.

Sources:

Excellent history and timeline of the Northern Spotted Owl controversy – https://foresthistory.org/research-explore/us-forest-service-history/policy-and-law/wildlife-management/the-northern-spotted-owl/

PNAS paper with the details – https://www.pnas.org/content/118/31/e2102859118

Oregon State University press release – https://today.oregonstate.edu/news/removal-barred-owls-slows-decline-iconic-spotted-owls-pacific-northwest-study-finds

I’m doing a lot of driving between my home in Maine and a healthcare facility in New Hampshire.  During that extensive windshield time, I am on the lookout for nature sightings of all sorts.  I’ve spotted ducklings, turtles, and fawns crossing county roads.  Along Route 95, I’ve notice hawks perched on tree branches and sometimes actively pursuing prey.

Red-tailed Hawk
Red-tailed Hawk Image by Djddphotography from Pixabay

Cruising along at 70ish miles per hour, I’m often going too fast to make an accurate identification of the raptors I see.  Or so I thought.

Pete Dunne’s Hawks In Flight was a revelation.  Interestingly, recognizing a bird’s size doesn’t really help when either the bird or you are on the move.  You also can’t see details such as eye color or notice eye-rings on birds in flight.  Consequently, the most common markers for identification won’t help.  The most useful keys include plumage characteristics, wing shape, wing beats, and manner of flight.  

There are some other clues too. First, in New England, most hawks on I-95 are going to be Red-tailed Hawks (Buteo jamaicensis).  These are also the most common hawks in this region, so this helps improve your odds.

Red-tailed Hawks appear stocky, with wide wings, a relatively short tail, and they display a white chest with an extensively streaked belly band.  This species should become your standard reference upon which you compare all others.

A few other raptor clues:  Osprey (Pandion haliaetus) have a crooked-wing silhouette.  Merlins (Falco columbarius) seem to sink as they glide.  A Sharp-shined Hawk (Accipiter striatus) in flight appears to be all wings and tail with no head.  

There’s a lot more to learn but I’m ready for the next drive!

The Common Loon (Gavia immer) achieves iconic status in my part of the country.  Its distinct wail prompts images of unspoiled wilderness.  A sighting on a lake evokes thoughts of solitude and grace.  The loon conveys such a definitive image that it is often used as a symbol for nature itself.  

However, we also know this is a special bird in an increasingly threatening environment.

Common Loon
Photo 96749559 / Common Loon © Brian Lasenby | Dreamstime.com

So, perhaps you will be surprised to learn that the Common Loon is not a federally protected species.  I assumed it was!  However, the birds are classified globally as a species of least concern.  If you are cringing as you read that, you are not alone. 

Loons are subject to several threats to their survival.   Sometimes, loons feeding on minnows mistakenly ingest lead fishing sinkers resulting in lead poisoning.  Boats also create another set of threats. Direct strikes are not uncommon nor are the boats’ wakes that can flood onshore nests.  In some locations, mercury in the water accumulates as a toxin in the fish that the birds eat.  Life is not easy for this symbol of nature.  

Consequently, there are many local conservation groups dedicated to raising awareness and it may be helping, at least a little.  

Consider the annual loon count results:  

  • In Maine, volunteers have been doing a snapshot count across the same slice of the state for 38 years.  While the 2021 count didn’t reveal a larger population than recent years, the loons have doubled their numbers since the dangerous low count of 1983.  
  • In Vermont, the loon population has steadily rebounded from a low of 8 nesting pairs in 1983 (yikes!) to 101 nesting pairs in 2019.  
  • In Minnesota, the loon population remains stable with an average of 2 loons per 100 acres of lake within the six survey areas. 
  • Sadly, another study in Ontario, shows the numbers continuing to decline.  

Loons are quite territorial.  According to a study published in the 1950s, a loon pair will occupy a territory of 15-100 acres, depending on the nesting site availability.  This territorial need creates a unique and perhaps bizarre behavior. 

Recently, a biologist in Minnesota reported observing that territorial loons (ones reproducing) intrude more often into neighboring territories where the nesting pair has chicks than do younger, non-territorial (non-reproductive) floaters that are looking to find and settle on an unclaimed territory.  One might think that the floaters would be looking to disrupt the reproducing loons, not another loon family.   

 A study published in Behavioral Ecology in 2006 also described this behavior.  After considering a couple of other reasons that might prompt this behavior, the research team believes that the intrusive loons are prospecting for habitat that they believe indicate reproductive success, proven by the presence of chicks.  One nesting pair will attempt to displace another to secure the best chase of success for their offspring!

Our uncommon, iconic loon appears to be among other things, a fiercely competitive parent.  

Sources:

More about loons in Maine – https://maineaudubon.org/news/the-2021-annual-loon-count-is-in-the-books/

More about loons in Vermont –  https://vtfishandwildlife.com/conserve/bird-survey-results

More about loons in Minnesota – https://loonproject.org/2020/11/14/a-key-finding-neighbors-are-not-friends/

More about loons in Ontario, Canada – https://www.thelandbetween.ca/2021/01/are-we-losing-the-loons/

More about territorial incursions by loons – https://academic.oup.com/beheco/article/17/6/881/316447?login=true

Great Blue Herons (Ardea herodias) hold a special place amongst my extensive list of favorite creatures.  They were one of the first birds I was able to name when most birds seemed unidentifiable.  Consequently, whenever I spy that striking blue-gray bird, I feel as though the world is alright at that moment.

So, imagine my surprise this morning when I spotted a GBH landing on the crown of the White Ash tree (Fraxinus americana) directly outside of my front window. This tree is old, singular, and quite a distance from the lake.  I could not fathom why the bird chose to land there. 

Great Blue Heron
Image by simardfrancois from Pixabay

I’ve never seen a GBH sitting in a tree that wasn’t part of its rookery.  My favorite rookery was in a wetland surrounded by an industrial area in northern Indiana, near the polluted Calumet River.  (It’s gone now.  It was active for 60 years before the herons moved on.) 

I’m pretty sure that the trees hosting the nests at that location were Black Ash (Fraxinus nigra).  This was a relatively small rookery of about 25 nests.  Large colonies can have more than 100 nests.  Regardless of the size, the scene is impressive.

Made of sticks, the nest is about 4 feet across and about 2 feet deep. The nest can be situated as low as 20 feet or as high as 100 feet above the ground or water.  The birds lay three to seven eggs sometime in April or early May and 60 days later the babies fledge.

Imagine researchers’ surprise to learn that GBHs intentionally build nests near Bald Eagles (Haliaeetus leucocephalus), their feared predators.  The rationale for this is counterintuitive.  Eagles will prey on GBH babies, but the eagles are themselves territorial and will chase away others within the vicinity of their nest.  This defensive behavior by the resident eagles results in some losses for the herons. However, the losses are fewer than if many eagles could swoop in unchallenged because it is unclaimed territory. This odd nest placement strategy by the GBH is called the predator-protection hypothesis and is seen in a few other species pairs as well.

In this part of Maine, we do have a GBH rookery close by.  We also have at least two pairs of nesting eagles whose territories appear to overlap the rookery’s airspace.  

Perhaps what I witnessed was a relatively young GBH hiding from a nearby eagle.  Or maybe he/she just needed a quick rest before heading back out to fish the lake.  In any case, the sighting was magical.

Source:

More info about Eagle-GBH interaction:  https://www.theatlantic.com/science/archive/2021/01/great-blue-herons-bald-eagle-prey-predator/617806/

 

Many birds rely on keen eye-sight or exceptional hearing to find food and avoid predators.  A bird’s sense of smell seemed to have only minor value, until now.  

White Storks
Image by Alexas_Fotos on Pixabay

A research team from the Max Planck Institute explored an idea that was intuitively known to local farmers.  When the farmers mowed their fields, the white storks (Ciconia ciconia) that lived downwind of the fields quickly appeared.  Mowing allowed the storks to more easily find the snails, frogs, and rodents they feed upon.  The storks were responding to the smell of the freshly cut grass.  

To ensure that the birds weren’t listening for the sound of the tractors, the team devised a few tests. For the first step, the research team included only observations of storks that arrived from a distance beyond the birds’ ability to hear the tractors. This suggested that they were relying on something other than hearing as the cue to come forage. 

Next, they spread freshly mowed clippings from a distant site onto the field, and again the storks appeared.   

In the last test, the team sprayed a field with a chemical mixture of green leaf scents that smell like cut grass.  The storks showed up again.  

The team concluded that the storks followed their noses.  This is not completely surprising as storks have an oversized olfactory section in the brain which also have many scent receptors.  The sense of smell deserves a bit more respect!

You can read more about the study here:  https://www.mpg.de/17069936/storks-smell

 

A new study out of the University of Central Florida reveals that nesting loggerheads and green sea turtles are smaller today than they were in the past.  Why this is, is unclear.

Loggerhead Turtle
Image by David Mark from Pixabay

About one-third of all green turtles and many loggerheads nest along Central Florida’s Atlantic coastline.  It is a critical breeding ground. 

Consequently, the shrinking size of the average nesting turtle is concerning.  

There are at least two reasons, one positive and one definitely not.  On the upside, it is possible that conservation efforts are succeeding and there are now more younger turtles coming to nest. If there is a significant population increase of these younger and smaller turtles, it will impact the average size measured by the teams that research and protect them. 

On the other hand, it may not be about an increased volume of new turtles.  Instead, young turtles could be growing more slowly because food sources are more scarce due to habitat degradation or competition.

More research is needed.  I’m hoping the teams will discover a turtle population boom. 

The related University press release is available here:  https://www.ucf.edu/news/ucf-study-finds-smaller-turtles-are-nesting-on-florida-beaches/

Have you ever wondered if you are creating a dependency by putting out birdseed?  I have. Well, worry no more. There’s good news.

Researchers at Oregon State University studied the winter feeding behavior of black-

Black-capped chickadee
Image by GeorgeB2 from Pixabay

capped chickadees (Poecile atricapillus).   Chickadees were chosen because they are small but they are frequent feeders.  This is because they have high daily energy requirements.  

To conduct the study, the team used a group of birds whose feathers had been clipped. These were the experimental group while non-clipped birds became a control group.  Then the birds were fitted with radio frequency identification (RFID) tags for tracking purposes.  

Feeders were offered to all the birds. Foraging in a natural environment was also an option. Then feeders were removed but foraging remained available.  Both groups did well.  There were sufficient environmental sources like seeds, berries, and small invertebrates even for the clipped birds.  The clipped birds were not reliant upon the supplemental food.  

It appears that feeders were just another dining option!

To read more about the study, here is the press release:  https://today.oregonstate.edu/news/don’t-worry-birds-won’t-become-dependent-you-feeding-them-osu-study-suggests

And here is the published study:  https://onlinelibrary.wiley.com/doi/epdf/10.1111/jav.02782

@ForAnimEcolLab

 

In other news, a team of researchers in Wisconsin quantified the reduction of deer–vehicle collisions (DVCs) as a result of restoring the local wolf population.  In Wisconsin, where the study occurred, the wolves’ presence reduced DVCs by an incredible 24%.  Interestingly, the reduction is mostly due to the deers’ behavioral change in response to wolves rather than through a deer population decline from wolf predation. 

This should give wolf detractors something to think about…the upside may be worth the risks.

To read more about their research, check out the PNAS article here:  https://www.pnas.org/content/118/22/e2023251118

 

Finally, there is a report about how an elephants’ personality plays a role in their problem-solving abilities and approaches.  I’m pretty sure I saw one of the participating elephants solving a puzzle on the television show, The Zoo, on Animal Planet.  The research team worked with 15 Asian elephants and three African savanna elephants at the San Diego Zoo, the Smithsonian’s National Zoological Park, and the Oklahoma City Zoo.

Asian Elephant
Image by Marcel Langthim from Pixabay

The elephants solved puzzles in exchange for a treat (a marshmallow, I believe).  They were asked to solve the problem three times.  Most solved them faster at each turn. The elephants also displayed a variety of measurable traits such as level of activity, affection, aggressiveness, defiance, excitability, mischievousness, shyness, and sociability.  Each of these may reflect components of their personality. 

The findings showed that traits such as aggressiveness and activity were important predictors of their overall problem-solving ability.  On the other hand, the personality traits did not predict the elephant’s ability to learn and subsequently solve the problems or do them faster. 

More fun puzzles and more treats will be needed to get to these answers. Now, don’t you think maybe the elephants are playing the researchers?  My dear departed dog would have gone to any length to get another treat.  Just saying. 

You can read more about the study here:  http://www.uwyo.edu/uw/news/2021/06/uw-researchers-elephants-solve-problems-with-personality.html

And you can see a video here, if you haven’t found the episode on Animal Planet.  This one features Chandra, the elephant mastering a water-based problem:  https://youtu.be/Pq882T6KMQ0

@lisapbarrett  @AnimalSmarts    @UWyonews

Noise created by humans often disrupts normal animal or bird behaviors.  Just consider the consequences of human noise pollution. Disrupting ocean life is but one example.  Sadly, the negative outcomes are well documented in whales, dolphins, and other sea creatures.

A team from California Polytechnic State University and Boise State University wanted to understand the role of naturally occurring soundscapes on the behavior of other animals.

This team, led by ecologist Dylan Gomes, tested a hypothesis that natural sounds influence where bats and birds live and forage. Bats and birds were chosen because they are sound-dependent for critical behaviors such as communication, navigation, and hunting.

To test their hypothesis, the team created rushing whitewater sounds where gentle

Stream in Pioneer Mountains
Photo by Robert Crum on Dreamtimes

streams typically flow. They chose 60 study sites within the remote Pioneer Mountains of Idaho and set up the equipment.  Then they generated the noise, varying loudness and audio frequency.  

The results showed that both volume and pitch (frequency) impacted the bats’ and birds’ ability to go about their duties.  Pitch is important because it may mask or overlap with birdsong, as an example.  Consequently, subsequent increases in either decibel (for volume) or kilohertz (for pitch) caused both species to decrease their foraging behavior.  Some bats and birds even move away from the study sites.  The violent rushing river sounds appear to have been too distracting to continue life as usual.

Birds that stayed in the area were less efficient foragers. They harvested fewer insects.  In comparison, some bats were a bit more adaptable and made adjustments. They shifted from listening for their prey to using echolocation.  Despite this shift in behavior, foraging success still suffered.

More studies are warranted but if these species are this sensitive to natural sounds perhaps we have underestimated the impact of our noise-generating activities. 

For another example of naturally occurring noise impacts on a species, check out this earlier post about the waterfalls and the frogs.  https://comfortmewithnature.com/nature-in-the-news-unexpected-nature/

Sources:

Article at Cal Poly site – https://calpolynews.calpoly.edu/news_releases/2021/May/birdsbats

 Research paper about this research – https://www.nature.com/articles/s41467-021-22390-y

 

@CalPoly   @BoiseState  

I have always been a nervous flier despite having flown hundreds of thousands of miles over several decades.  (Yes, I’m THAT old.)  Turbulence, among other things, unsettles me.  I know I am not alone in this fear though I never considered the impact of turbulence on birds. 

As we know, turbulence means the airflow is changing direction, much like currents in the water.    It can scale from tiny swirls to hurricane winds and features eddies and vortices.  They occur because of weather patterns, geographic features such as mountains, or simply when warm and cooler air collide. 

Using this information, a group from Cornell University studied the

Golden Eagle
Photo by Kevinsphotos on Pixabay.com

impact of turbulence on birds.   A captured golden eagle fitted with a solar-powered GPS tracker served as their inflight data source.  

Dr. Gregory Bewley, an assistant professor in the Sibley School of Mechanical and Aerospace Engineering, interpreted the eagle’s reactions to turbulence.  He noted that the bird likely anticipated the disturbances and adjusted its flight behaviors in synchronization with the changing airflow.  This synchronization appears to result in greater flight efficiency, including increasing acceleration with little effort. 

Dr. Bewley noted that if this principle applies to this large bird, it will most likely apply to smaller birds as well. 

A bird’s superior understanding of one of the earth’s dynamics is on display once again. 

For more information check out the press release from Cornell – https://news.cornell.edu/stories/2021/06/turbulence-gets-eagles-speed

Here is the PNAS paper – https://www.pnas.org/content/118/23/e2102588118

@CornellEng   @CornellNews

 

While we are airborne so to speak, let’s talk about a case of mistaken identity. 

Identifying a new species must be a thrilling experience but confirming the novelty isn’t always a certainty.  

In the 1870s, a rare bee specimen was uncovered in Nevada.  Since then, it was known as the rarest bee in North America.  Only one was ever found, until now. 

Photo by Katharina Notarianni on Dreamstime.com

A team from Canada, examining the specimen, realized that that one bee was an aberrant example of a much more widespread species known as the California digger-cuckoo bee (Brachymelecta californica).  

The unique individual had different colored hairs and wing features.  No wonder folks thought it was a different species.   Alas, it was not. 

To read more about this, check out the release from the Canadian Museum of Nature – https://nature.ca/en/about-us/museum-news/news/press-releases/case-mistaken-identity-solved-rarest-bee-genus-north-americ

@MuseumofNature

Birds are in the news spotlight this week.  A report published in the Proceeding of the National Academy of Sciences describes the first comprehensive effort to accurately estimate the total number of birds for approximately 9,700 different species or 92% of all species known to exist.  Collectively, there are roughly 50 billion individual birds in the world.  

To determine the relative abundance of each species, researchers from the University of New South Wales used citizen science data from sightings recorded in eBIrd.  The data was aggregated from January 2010 through May 2019.  Range maps were used to adjust population areas.  From there, some careful mathematical modeling based on multiple factors informed how the team calculated the bird population density. 

Four bird species — only four — each has populations that exceed one billion members.  These include House Sparrows (Passer domesticus), European Starlings (Sturnus vulgaris), Ring-billed Gulls (Larus delawarensis), and Barn Swallows (Hirundo rustica).  The top 10 species account for just shy of 10 billion birds.  This means that 0.1% of bird species account for 20% of the entire bird population.  Conversely, 12% of all species have fewer than 5,000 individual birds.

The research team believes that beyond the value of knowing how many birds there are by type, perhaps more importantly, their methodology can be used to estimate the quantity of almost any other organism in the world.  This will be a powerful new tool for environmental and conservation strategy and management. 

To read more about the methodology of this study, see this PNAS paper here:  https://www.pnas.org/content/118/21/e2023170118

@UNSWScience

 

One of the birds that was counted was certainly the Griffon Vulture (Gyps fulvus).  About 50 years ago, this large bird of prey, became extinct in Bulgaria.  But a restoration effort begun in 2009 has successfully reintroduced breeding pairs into the Eastern Balkan Mountains.  

From the beginning of the program, a total of 135 Griffon Vultures that were recovering or captive-bred in zoos and rehab centers were released.  As of December 2020, breeding pairs have produced more than 30 wild-born chicks that have fledged.

The reintroduction effort has been declared a success, despite a 33% mortality of those released.  The vultures still need support, including supplemental feeding. Despite the challenges, the birds are making these mountains theirs again.

You can read more about the reintroduction here:  https://bdj.pensoft.net/article/66363/

@greenbalkans

Locally, the activities of birds seem to be approaching their peak for the season.  We continue to see migratory birds passing through, others arriving for the summer, and others building their nests.  

You may have noticed that one bird or even several birds seem to be nearby whenever you are outside or looking out the window.  Take note of who these are.  Your challenge will be to observe them throughout the rest of the season.  

Let me share some examples with you from our own experiences.  As I’ve already mentioned, we have a pair of house finches that are struggling with nest-building.  (See https://www.comfortmewithnature.com/house-finches-nesting-behavior/)  They continue to stop by the porch eves, the pellet stove exhaust pipe, and the lilac bush at least several times a day.  However, they seem to have abandoned that particular nesting site.  We will try to find where they have attempted another.   

These are not our only frequent bird visitors.  We also have an Eastern Phoebe that Eastern Phoebeloves to sit on our porch railing as a spotting site for flying insects.  (Yes, our porch is a veritable wildlife hotspot.  I haven’t even mentioned the porcupine that came to the kitchen door, among others.)  Most years, we have the trio of turkeys and their seasonal brood that seem to enjoy foraging in our front yard.   

There is also a plethora of other birds including blue jays, robins, and ravens, but there are so many of these that it is difficult to track the activities of any one or pair.  Others such as hawks and owls have too large a territory to consistently follow their actions. 

One of our favorite observation subjects is a red-throated hummingbird.  He arrived a few days ago after the rhododendrons started to bloom. He frequently sits atop the large lilac bush in the backyard.  Once it flowers, he will harvest the nectar.  Sometimes, for no obvious reason, he will hover and inflate his red throat.  It is an incredible sight.  

We suspect that this is the same hummer that has returned the last few years.   Since hummingbirds have a lifespan of 3 to 15 years, I am hopeful that we will watch this one for many more.  

Now it’s your turn.   Who is visiting your yard regularly?  Remember to take some notes.  You never know if you might record an unusual event or behavior.  You too could advance our understanding of nature.   

This challenge is rated as moderate.