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Thursday, April 23, 2020

Bird Feeders: Sharing Our Earth with Wildlife

This Earth Day I want to focus on birds.  Birds are by far the most successful vertebrates on land today.  They outnumber all other vertebrates, including us, mammals, in terms of species diversity, as well as in sheer numbers.  With this in mind, paired with the fact that birds are dinosaurs, you could say the "age of dinosaurs" people often think ended millions of years ago, is still going stronger than ever.  A great way to see a wider variety of live dinosaurs without even leaving your home is by setting up a bird feeder.  Feeders come in a variety of sizes and types and can be set up even on windows of small apartments if need be.  I put together a list of thoughts to remember that I hope will help you get the most out of your bird feeder.

A Tufted Titmouse (left) and female Downy Woodpecker (right) sharing a meal at our feeder.  

Tip 1: Feeding wildlife is dangerous.

First off, I want to make it clear that most of the time it is an absolutely terrible idea to feed wildlife.  Normally when this happens, wild animals learn to associate humans with food, and therefore will start seeking humans out instead of foraging for food, themselves, like they naturally would be.  This is how you get what are referred to as "problem animals", like deer, bears, or even alligators, that lose all fear of humans and start living way to close to people for comfort.  Sadly these animals are often humanely killed by local authorities because they start posing a threat to people.  In addition to this, well-meaning people often feed wildlife inappropriate foods that don't meet the animal's nutritional needs, and in some cases actively hurt the animals.  Feeding bread to ducks, for instance, is actually detrimental to the ducks since they can't digest it and it can lead to developmental problems.

Snow White was super inappropriate when it came to interacting with wildlife.  Don't be like Snow White. 

Tip 2: Wildlife Still Needs Our Help.  It just needs to be given the right way.

Hold on...I started by saying I was going to tell you how to set up a bird feeder...but then said feeding wildlife is bad?  Which is it!?  Let me explain.  Bird feeders are a little different from blatantly throwing food at animals outside since in the case of bird feeders, the wildlife never associates the food with humans.  As far as the birds know you and the food you put out are completely unrelated.  This fact, paired with the assumption that the quality of food you're providing the birds is appropriate and adds to, not replaces, their wild diet (which we will cover below), results in a totally safe scenario for all parties, with some added food available for the birds, and entertainment for you!  I'm a firm supporter of the idea that wildlife should stay wild.  However, I also completely support the idea of humans actively helping protect and preserve wildlife when it's needed and if it's done appropriately.  Wild bird numbers have been consistently dropping at an alarming rate and it's absolutely in response to human activity, predominantly pollution, habitat destruction, and climate change.  So putting a bird feeder out is a small way to maybe help some wild birds get some extra energy and nourishment in their already stressful daily lives living in the wild.

Tip 3: The variety of animals present is entirely dependent on the habitat available.

In order for wildlife to be present there must be a habitat.  It sounds like a no-brainer, but it's important to keep in mind. The kinds of birds that will come to your feeder will depend on the kind of habitat you are currently near.  That being said keep in mind that urban areas with lots of human development are absolutely habitats for wildlife, too.  I have seen lots of really interesting species that make their homes in highly populated cities.  If you do live on a property where you have a yard and the ability to control the kinds of plants and landscaping that's present, you can change the habitat and possibly attract more species over time.

Habitats are less restricted by space than you think.  This is important especially if you live in a small home with no yard, or in an apartment.  This doesn't mean you can't still provide at least a small change to make your home a little better for wildlife.  Many flowers and other native plants do just fine in potted plants that can exist on windowsills.  Bird feeders that attach directly to windows via suction cups are easy to find and purchase.  My point is no matter what kind of home you live in, attracting more wildlife is always possible.

Eastern Bluebirds only nest in meadows and fields, so if you don't have a space like that nearby, you are unlikely to see them very often.  I took this photo miles away from my house because I don't have the right habitat near my property for this species.

Tip 4: Insect protein is essential for nutritious bird feeders.

The more variety in food is in your feeder, the more variety in wildlife you'll attract.  Lots of people simply buy a bag of seeds to fill their feeders.  If you really want to attract more species of birds, as well as provide them with more useful nutrients, make sure your bird feeders have insects in them!  Keep in mind that in the wild, many songbirds eat a lot of insects.  In fact, songbirds, even the ones that are often associated with eating seeds and fruit, are one of the strongest forces that control insect populations in the world, alongside bats and amphibians.  Luckily any garden store, or other place that already sells wild bird seed, will have bags of dried mealworms that you can mix into your feeder.  Some bird feed companies also make bags that include both seeds and insects together.

Downy Woodpeckers, like all woodpeckers, eat insects year round.  A suet block, like the one this male is feeding from, is essentially a powerbar for birds, loaded with protein from both ground nuts and insects.  

Tip 5: You don't need to hate on squirrels so much.

I see people often complaining that they get too many squirrels eating out of their bird feeders. I've even witnessed many people state they actively avoid setting up bird feeders because they're so turned off by the squirrels.  Where I live we have Eastern Gray Squirrels.  They're extremely common, but they're still native, and therefore a part of the natural environment.  They help plant trees by burying seeds and nuts (and forgetting to retrieve them) as well as provide a valuable food source for many charismatic predators, like hawks and owls.  In addition, even though it may seem like squirrels are hogging all the bird seed, I assure you the birds are still getting meals out of the feeder.  That being said if you still want to reduce the frequency of squirrel feeding and increase that of birds, many bird feeders have mechanisms that (somewhat) deter squirrels built into them, like perches that collapse under the weight of a squirrel, but not a bird.  You can also buy bird seed that has hot peppers in it which squirrels don't like, but birds do.  That's right.  birds have different taste receptors from mammals, including the inability to register capsaicin, the chemical that makes you feel like your mouth is on fire when you eat spicy food.  (When I was a zookeeper the cockatoos LOVED to snack on chili peppers.)

The neighborhood we live in has a high concentration of melanistic Eastern Gray Squirrels.  Melanism is when an animal is born with more melanin, the pigment that makes skin and hair darker.  


Tip 6: Clean your bird feeder between fillings.

When your bird feeder is empty, scrub it thoroughly with soap and water and let it air dry for a day before you fill it up again.  Old food residue will start to harbor bacteria and fungus that will make birds sick when they use the feeder.  Not letting the feeder dry all the way before filling will also grow fungus that can be harmful to birds.  Same goes for hummingbird feeders.

This is a male and female Eastern Goldfinch that visits our feeder almost every day.  This photo was taken in early March, and you can see the male wasn't quite shedding away all of his brown winter feathers for his bright yellow mating season feathers.  The female, although more drab than the male, also turns more yellow in the warmer months. 


Tip 7: Don't be surprised if your bird feeder becomes a bird feeder... feeder.

By this I mean that if you have songbirds visiting your feeder enough, their predators will start to hang around too for obvious reasons.  Since putting up my feeder this past winter, I see the local Coopers Hawk and a young Red-Shouldered Hawk showing up more often.  As with the squirrels, some people don't like birds of prey at their feeders because they feel bad for the pretty songbirds that are at the feeder.  In my opinion it is important to keep in mind that regardless how cute these little birds are, they are still an active piece in the local ecosystem, and being food for a predator is an inevitable and necessary fate for some of them.  After all, the predators need to eat too.

Predators of songbirds, like the Barred Owl I photographed in October, are a necessary part of any ecosystem.  Owls especially also heavily control rodent populations.

Tip 8: KEEP YOUR CATS INDOORS!!!

There is literally no positive aspect of having an outdoor cat.  None.  Not for the cat, and certainly not for any wild animals that now have to share space with the cat.  A recent scientific study came out that proves just how many birds and other native animals domestic cats really kill and the numbers are horrifying.  It's estimated that domestic cats are responsible for the deaths of BILLIONS of wild birds per year.  Billions.  With a B.  That's more bird deaths than by window collisions!  Some might argue that an outdoor cat is simply part of the environment and doing its part as a predator.  This opinion is extremely wrong for a few reasons.  First of all, domestic cats are originally native to Northern Africa, from where they spread to there rest of the globe with humans as pets, and therefore have no business in most ecosystems where they're killing birds.  So this is why outdoor cats are such a problem, but the birds of prey that also kill small birds I previously mentioned, are not.  Second, even if you were to try to reason that cats are taking the place of other predators that previously lived in these areas before humans developed over them, like bobcats, you'd still be wrong.  This is because one bobcat can have a territory that stretches for several miles which they will defend from other bobcats violently.  Plus, although Bobcats do eat birds naturally, they don't kill them nearly as frequently as one domestic cat does.  Domestic cats also aren't nearly as territorial so many individuals can be roaming the same small space, and since they're often being fed by their humans anyway, they're killing birds out of instinct/play, not to survive.  Another important point is that being outdoors unsupervised is extremely dangerous for the cat, as well.  Typical lifespans of cats that are allowed to roam outdoors are significantly shorter than those of cats that stay indoors.  They're exposed to parasites, fleas, all sorts of diseases, and of course are at risk of being killed by cars and even wild predators, like coyotes and even large birds of prey.  If you're a cat owner like me, you can keep your cat perfectly happy indoors with toys and plenty of attention in the form of play sessions with you, the owner.  You can also totally get your cat used to a leash for outdoor adventures that is safe for both the cat and the local wildlife.

One of our cats, Beaker, wasn't a fan of the leash at first, but now she loves her (wildlife-safe) outdoor adventures.

Tip 9: Citizen Science is fun.

Citizen science is when amateurs or non-professionals participate and contribute to scientific research.  This can take lots of forms, like volunteering at your local nature center to help gather data on local wildlife populations.  However, some citizen science can be done without even leaving your house, like something as simple as counting the number of birds that visit your feeder.  Free apps like ebird and iNaturalist allow you to document bird numbers and species as you see them, and scientists can use that data for their research.  Not able to identify every bird that you see?  No problem!  Both these apps have features that actually help you identify mystery animals in real time, so you're learning to identify local wildlife you share your home with, too.  It's also fun to rack up as many bird species as possible and compare to other folks doing the same thing in their homes!

Northern Cardinals, like this female who visited our feeder yesterday, use their powerful beaks to crack open shells of nuts.
I hope this list of tips helped inspire you to start your own bird feeder.  If you already have a feeder I'd love to know what kind of visitors you're getting.  I personally have spotted a total of 28 species at my feeder since setting up this past winter.  Share your species count or the coolest bird you've seen on your property in the comments below!

Sunday, April 19, 2020

Pterodaustro: Beast of the Week

This week we will be taking a look at a bizarre pterosaur.  Let's check out Pterodaustro gulnazui!

Pterodaustro was a pterosaur that lived in what is now Argentina, during the Cretaceous, about 105 million years ago.  Adults had a wingspan between eight and nine feet long and they would have likely eaten meat in the form of very small animals (more on that in a bit).  The genus name translates to "Wing from the South" and the species name honors paleontologist, Roman Gulnazu.

Pterodaustro life reconstruction I produced in watercolors.  Because this creature was likely a filter feeder it is often restored with pink coloration, like a modern flamingo, but many other animals that filter feed, like ducks, do not become this color and there is no reason to think Pterodaustro was more likely pink than not.  

Pterodaustro is a well-studied pterosaur.  It is known from multiple complete skeletons, including adults, juveniles, and even eggs with embryos still inside.   Thanks to this array of specimens paleontologists know a lot about this strange creature's life appearance and growth pattern.  

 By far the most striking feature about Pterodaustro is its face, particularly its mouth.  This pterosaur sported a long, thin beaklike mouth that gently curved upwards.  Growing up from the lower jaws were over a thousand bristle-like structures.  These structures, although hair-like, were actually highly specialized teeth.  It is thought that Pterodaustro used these modified teeth for filter feeding tiny creatures out of the water, much like a modern flamingo, or some whales do with baleen.  Pterodaustro also had very small, teeth on the upper jaws, possibly for processing its food after trapping it in the mouth with its unusual lower teeth.  A few Pterodaustro skeletons were found to have tiny rocks in their stomach cavities.  Many reptiles, including dinosaurs, lizards, and even modern birds, are known to swallow tiny rocks, called gastroliths, which help aid in crushing up food inside the stomach or crop once eaten.  Pterodaustro is the first example of a pterosaur that also did this.  Because of these rocks, it is implied that the food Pterodauestro was eating wasn't soft, so it was probably specifically filtering tiny crustaceans that sported exoskeletons that needed to be crushed and broken after capture.

Pterodaustro skeletal cast on display at the Museo Argentina de Ciencias Naturales in Burinos Aires, Argentina.

Pterodaustro had a long, thin neck and a relatively long torso for a pterosaur.  Its hind legs were proportionally short so it may not have been a very fast walker.  In order to get into the air to fly, takeoff also would have been relatively difficult because its short legs would have hindered it from launching very far from the ground.

The Pterodustro eggs on the fossil record are similar to other known pterosaur eggs in that they would have had somewhat soft shells, more similar to those of modern turtles than birds.  The babies would have only been a few inches long when first hatched and would have grown very quickly for their first two years of life until they became sexually mature.  They would have continued to grow at a slower pace for four to five more years.

That is all for this week!  As always please leave a comment below!

References

Chinsamy, A., Codorniú, L., and Chiappe, L. M. (2008). "Developmental growth patterns of the filter-feeder pterosaur, Pterodaustro guinazui"Biology Letters4 (3): 282–285.

Codorniú, L., Chiappe, L.M., Arcucci, A., and Ortiz-Suarez, A. (2009). "First occurrence of gastroliths in Pterosauria (Early Cretaceous, Argentina)". XXIV Jornadas Argentinas de Paleontología de Vertebrados

John D. Currey (1999). "The design of mineralised hard tissues for their mechanical functions". Journal of Experimental Biology202 (23): 3285–3294.
Witton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press.