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Predicting that next winter finch irruption

Pine Siskin - Spinus pinus

A Pine Siskin, a regular but unpredictable visitor in winter in South Dakota Research shows that southward irruptions of boreal finches such as Pine Siskins may be predicted from recent seasonal climate records.

Not a lot of time this week to blog, as I’ve been in pretty intense meetings all week for work.  However, it was through those meetings that I became aware of this interesting research paper.  Birders are always wondering when that next great “irruption” of boreal bird species will occur.  On occasion, boreal finches such as Common Redpolls, Pine Siskins, and Crossbills will move southward in great numbers from their boreal forest stronghold.  The thought is that such irruptions occur when poor “mast” production occurs, with lower conifer seed numbers than normal.  The birds thus move southward in search of food.

It’s not just boreal finches that are subject to occasional southward irruptions.  One of the greatest birding experiences of my life was during the huge boreal owl irruption into northern Minnesota over a decade ago, when Great Grey Owls and Northern Hawk Owls were seemingly “dripping off the trees”.  Those irruptions are thought to be due to a similar driving force…a loss of a primary food source…with periodic crashes of small rodent populations driving the owls southward in search of food for the winter.

The paper below (click to see it) gives an assessment of climate data to potentially predict when a finch irruption would occur.  The species studied here is the Pine Siskin, but the authors note that it may also apply for other boreal finch species that depend on conifer mast.  Cool study…

More coming next week!  Given I’m still in meetings the rest of the week and have family obligations all weekend, it’s likely the next blog post won’t come until Monday!  Click below for the study…

Predicting finch irruptions with climate information

In the News – Week of January 1st, 2017

A new year, a new set of nature and science news pieces for the week…

Black-tailed Prairie Dog - Cynomys ludovicianus

A “varmint”, a Black-tailed Prairie Dog. I have on several occasions run into “sportsmen” in South Dakota who are lined up at the edge of a prairie dog town, picking them off one by one with rifles. Killing for the sake of killing…and doing twice the intended harm, given the lead that’s ingested by predators when they eat the carcasses.

Ammunition choice in shooting “varmints” — There have been many occasions on my birding trips to the central part of the state where I come across a sight that makes me sick to my stomach.  I’ll drive past a prairie dog town, and see multiple hunters lined up along a fence line, crouched and in a shooting position, picking off prairie dogs for “fun”.  That’s it…there’s no other purpose to it, other than killing for the sake of killing.  The prairie dogs that are killed aren’t used for anything, they’re simply left to rot.  Unfortunately, “sportsmen” who feel this sick need to kill for the sake of killing end up doing even more harm to animal communities.  By leaving the dead bodies, it provides an avenue for predators to consume the dead prairie dogs, and ingest the lead in the ammunition that was used to kill them.  Lead poisoning is a major cause of mortality for many raptor species, and is THE leading cause of California Condor mortality. A simple solution, as this article points out, would be to use ammunition that’s free of lead.  Even that common-sense approach though, one that still allows redneck hunters to kill prairie dogs and other “varmints”, is hated by hunting groups, as they claim that lead alternatives in ammunition don’t perform as well as lead shot and bullets.  Given what I have come across over the years on all my birding excursions, I’ve had a major downturn overall in my attitudes towards hunting…and particularly…hunters.  Stories like this don’t help my perceptions of hunters.

Cheetah numbers down to 7,100 worldwide — Over the last century, cheetah numbers worldwide have dropped from 100,000, to only 7,100 today.  Think about that…in a world with nearly 7 billion human beings, for an iconic, well-known predator such as the cheetah, there are only several thousand left. As with most species’ declines, habitat loss is behind the cheetah’s loss in population.  They range over huge territories, and there simply aren’t “huge territories” available in most parts of their range any more.  Throw in targeted persecution, such as the shooting of cheetahs by poachers and farmers, and this story estimates cheetahs could be extinct in the wild in 20-40 years.

Goldenrod Soldier Beetle

Is this the face of Earth’s largest animal migrations? This is a Goldenrod Soldier Beetle from here in South Dakota, and I admit I have no idea if these “migrate” as with some beetles mentioned in this story. By sheer mass, however, this story points out that insect migration likely dwarfs any other migration on the planet.

Biggest migration of land animals on the planet — When you think of what creature may make up the largest migration of any land animal on the planet, in terms of sheer mass, what species do you think of? Or group of species?  When you say “migration”, most people probably think of birds first, and there certainly are mass migrations of birds that are so heavy that weather radar is being increasingly used as a tool to study those migrations. In terms of sheer mass, perhaps some people think of large caribou migrations.  However, as this study notes, one overlooked migration likely has all of these beat…insect migration.  This study notes that around 3.5 trillion arthropods migrate over southern Great Britain each year, accounting approximately 8 times the mass of bird migrations in the same area.  Some winged insects are well-known for their migratory talents, such as the Monarch Butterfly in North America.  But as this study notes, there all sorts of winged and even non-winged creatures that migrate through the atmosphere.

What the heck is a “species” anyway? — People are funny.  We have this intrinsic need to categorize things, put them in neat little bins that help our minds process realty.  Birders sometimes take that to an extreme, with “life lists” that are often incredibly detailed, with “big day” lists (how many species you see in one day), “big years”, “state lists that detail bird species seen within the confines of state boundaries, and more.  What gets bird listers in a tizzy?  Just what IS a species!  The American Ornithological Union and American Birding Association are always making tweaks to their “official” lists of species that have been found in North America.  Just watch birders heads collectively explode if the AOU or ABA does decide to split Red Crossbills into up to six distinct species…life lists will be substantially increased!!  Even with the science of DNA-based splits, it’s still not a precise science in determining what’s a unique species.  As with many things, we’re categorizing things into unique thematic categories, when the phenomena you’re measuring is actually a continuous variable with no definite boundaries.

One, maybe two new comets moving through — Speaking of birders and their lists, I have a friend at work who is a birder, and someone who has a life list.  He also has another, more unusual life list posted on his bulletin board in his office…his “comet life list”!  He’s about to get one, and maybe two new ones for his list.  Comet C/2106 U1 was recently discovered by the “NEOWISE” project, and is potentially visible with binoculars right now, through about January 14th. It would appear in the southeastern sky just before sunrise.  An object called 2016 WF9 was also discovered by NEOWISE, and it will come close to Earth’s orbit in late February.  It’s estimated to be 0.5 to 1.0 km in diameter.  Note the designation “object”, because it’s not clear whether this object is an asteroid or comet (related to the previous story, in that the categorization of what’s a “comet” and what’s an “asteroid” can be fuzzy).

Bird Dropping Moth - Caterpillar - Ponometia

A caterpillar of Ponometia…the “Bird Dropping Moth”. Should a new species of “shit moth” be discovered, I would suggest it be named after Trump, in the same manner that several creatures have been named after Obama in recent years.

Nine creatures named for President Obama — Over the last few years, no less than 9 different creatures have had scientific names that honor Barack Obama.  Multiple fish, a lizard, bird, etc…all have scientific names such as “Nystalus obamai” (A Western Striated Puffbird, in this case). Once Trump leaves office in 4 years (or in a perfect world, once he’s impeached after a year or so), I wonder what creatures will be named after him?  I have many, many classes of creatures where new discoveries should consider his name. There are the Onychophora phylum of worms known for excreting slime. There are the Annelidas…leaches…which would be a wonder creature to name after him.  There’s a moth called Ponometia, and it’s associated caterpillar, that would be good.  Their common name is the “Bug-dropping Moth”.  Naming him after shit would be a perfect way to “honor” him once he leaves office.

Where you’re most likely to get struck by lightning — We had a very unusual Christmas day in South Dakota.  I believe it was 4 years ago when we were absolutely smothered in snow, getting close to 2 feet on Christmas.  We’ve had Christmas’s where the temperature never got above zero.  And then there was this Christmas where we had…a thunderstorm?  In late December? In South Dakota?  We set a record for most rainfall on Christmas Day, getting over an inch in most areas, and the lightning and thunder was the first time that’s ever occurred here on Christmas (or late December for that matter).  I could go into global warming here, but no, the point is the story in the above link.  Standing outside on Christmas Day in South Dakota normally isn’t a high-risk endeavor, in terms of being struck by lightning.  So where are the most active areas on earth for lightning?  Thanks to a satellite called the Tropical Rainfall Monitoring Mission, we now know.  The winner…a Lake Maracaibo in Venezuela.  Over each one square kilometer in the area, one could expect over 230 lightning strikes per year.  The lake is surrounded by mountains, and nearly every night, cool airflow from the mountains hits the warm waters and air above the lake and produces thunderstorms.

Western Meadowlark - Sturna neglecta

A Western Meadowlark, taken with a temp of -10° near Presho, South Dakota, in the winter of 2003-2004. I have a billion Meadowlark photos, but specifically remember this one because it was so rare to SEE one in the heart of winter. Now? They’re everywhere.

Bird migration changing with climate — As I noted in a previous post, I went birding to the central part of the state last week, and was amazed at how many Western Meadowlarks were around.  15 years ago, it was rare to spot one in winter in that part of the state.  Now…I saw hundreds, all across the region.  Global warming? It’s hard to ignore signs like that.  As this story describes, many birds are changing their migration patterns as the climate changes. Many are arriving on the summer breeding grounds much earlier than they used to.  There are also some species where migrations have become shorter, or perhaps such as the case of the Western Meadowlarks, where they’ve simply stopped moving south for the winter.

China bans ivory trade and purchase — A rare bit of good conservation news.  This last week, China announced that they will ban the sale and trade of ivory by the end of 2017. China was by far the largest market for legally sold ivory, with ivory selling for over $1,000 a kilogram.  The Great Elephant Census recently published noted that elephant populations world-wide plummeted by 30% in just the last 7 years (!!!!!), and incredible population decline for such a short time period.  With the shutting of the largest legal ivory market, it’s hoped that poaching pressures will decline.  However, it’s hard to guess what will happen with ivory trade, and if much of this will simply move to the black market.

Predicting that next invasion of winter finches

Common Redpoll - Acanthis flammea

A Common Redpoll, one of several “northern finch” species that sporadically invade the conterminous U.S. With this study, perhaps those irruptions could be predicted in the future.

It was 2 winters ago that we had an incredible redpoll invasion.  I’d never even had one in my yard before, and we’d lived in South Dakota for 20 years.  However, in the winter of 2013/2014, we had Common Redpolls around for several months.  A real thrill when one, and then another, Hoary Redpoll showed up at my feeders and stayed for a couple of weeks.

Such events are always a surprise, and it’s not just Redpolls.  Both Red and White-winged Crossbills are equally unpredictable winter invaders across the U.S., as are Pine Siskins and Evening Grosbeaks.  It was generally understood that large movements southward in the winter were due to poor seed crops for pines and spruces further north.  A new study from the University of Utah attempts to explain the winter invasions, based on climatic variables. First, the study finds that favorable climate patterns tend to shift across the continent. When one region is favorable to seed production, other parts of the continent are more likely to have unfavorable conditions for seed production, resulting in periodic movements in birds as they key in on areas with the most food resources.

The other climate finding is that it may be possible to predict irruptions to south up to two years in advance!  Seed production itself tends to be correlated with favorable conditions 2 or 3 years PRIOR to the actual growing season.  So, for example, if 2015 has unfavorable climate conditions in much of Canada, it may mean reduced seed production in 2017, resulting an increased likelihood of a southward irruption of northern finches. One of the things I love about birding is the total unpredictability, as you never know what you may see when you head out, but it would be cool to be able to anticipate a great winter finch season.

One final aspect of the work I like…they relied very heavily on eBird data.  A GREAT resource, but one that really isn’t being used for research nearly as much as other, more established monitoring programs like the Breeding Bird Survey.  If found the eBird data to be invaluable for the bird/climate/land-use study I published, and I think you’ll see more papers like this finch study use eBird data in the coming years.

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