Monthly Archives: April 2018

Meet Ferdinand

Around this time last year I was both delighted and intrigued when a reader emailed me about a very usual crow showing up in her yard.  Unlike its flock mates this crow was not black, but white and brown, like the kind of milked-down coffee that inspires the comment “would you like some coffee with your cream?”.  Understanding what would cause such a unique coloration in her crow sent me down a most unexpected rabbit hole where the science of what I call ‘caramel crows’ turned out to be somewhat subject to mystery.

Within months of publishing that article, I couldn’t believe my luck to encounter a caramel crow of my own named Blondie.  Whereas the science of their pigmentation may be up for debate, their beauty most certainty is not and I considered myself exceptionally lucky to lay eyes on one in person.

Photos of Blondie from 2017

Now, it seems my perception of their rarity may not have been quite justified as I have since discovered yet a second caramel crow, who I call Ferdinand, in a completely different part of the city.  Unlike Blondie, who lives exclusively in a residential area, Ferdinand’s haunts include a public park.  I won’t give his or her precise location, but if you’re a Seattle native I encourage you to use the clues provided in the text and photos of this post to see if you can find Ferdinand.  If you do use the hashtag #FoundFerdinand to update us on its activities but remember not to give away its precisely location.  This is both to encourage people to get outside and explore on their own, and to protect Ferdinand’s safety.  If seeming him in person is not possible I hope these photos will suffice.  As a last bit of fun feel free to let me know in the comments who you think wore it better, Ferdinand or Blondie.

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Filed under Birding, Crow curiosities, Just for fun

The birds and the bees

~This post describes sex in explicit terms ~

It’s springtime in Seattle which means the air is marked with the scent of warm, wet earth, the cherry trees are in full bloom, and our conversations of the goings on in the natural world are couched in the phrase “the birds and the bees”.  While its origin story is not completely clear, it’s very likely that this euphemism has been around for hundreds of years, dating back as early as 1644 in the Evelyn Diaries.  Despite the phrases’ ubiquity for discussing human sexuality, ironically very few people know much about the sex lives of the phrase’s subjects.  This is attributable largely to the fact that how these animals procreate is quite different from the mammalian systems we are familiar with.  So in the spirit of springtime let’s talk about the birds and the bees, the real story of the birds and the bees.

Birds
The most consequential departure by birds from mammalian systems is that most birds lack any kind of external sex organ. In contrast, most other kinds of animals have sex organs that are either maintained outside the body permanently, or can emerge temporarily as needed. Among birds, there are exceptions to this but fair warning you’ll probably never look at a duck in the same lighthearted way again if you pursue this line of knowledge. Which is to say of course that you absolutely should.

As far as crows and other songbirds are concerned though, sex must be conducted without penetration by a sex organ. So instead, these birds copulate by way of the “cloacal kiss”.  The cloaca is a bird’s single external vent and it’s used for both waste elimination and reproductive activities. During the breeding season, both the male and female’s vents swell.  To copulate, the male mounts the female and pushes her tail aside with his.  Once they make cloacal contact, the sperm that’s been stored in his cloaca is transferred.  It’s an awkward looking balancing act that lasts only a few seconds.  After the initial copulatory event the pair may mate again several times within minutes or over the course of weeks.

Whereas people need to consider timing, birds can successfully mate even in the absence of ovulation.  That’s because females have specialized sperm storage tubes inside their oviducts.  A female’s vagina is very picky, however, and only a very small number of the male’s sperm will reach this holding chamber.  Depending on the species, once there a female can store the living sperm for weeks or months. The exact mechanism of how the sperm are subsequently released is not entirely known, but possibilities include that it’s the mechanical pressure of the passing ovum (unfertilized eggs) that releases the sperm, or that it’s directed by hormonal changes during ovulation.1

One additional consequence of sperm storage is that it allows for different eggs within the same clutch to be sired by unique males.  In crows for example, about 80% of a nest has been sired by the female’s permanent partner.  It is unclear how many of these extra pair copulations are either solicited by or forced on the female.

Bees
While mid-air copulations have never been confirmed in birds, honey bees do in fact mate on the wing during what’s called the mating flight.  A newly minted, week old queen will take to their air followed by thousands of male drones.  She will only mate with about 10-20 of these individuals though.  To mate, the male inserts his endophallus (bee penis) into the queen’s sting chamber.  Once he has deposited his sperm, the male detaches.  Unfortunately for the male, however, he doesn’t do so with all the parts he arrived with.  His endophallus will rip off and remain inside the female, most often killing him.  As if that wasn’t brutal enough, the next male is required to remove the previous suitor’s leftovers before being granted the ability to seal his own fate.

By the end of the mating flight, the queen will be carrying hundreds of millions of sperm, most of which will be used immediately to begin fertilizing her eggs.  Like birds, the queen has a specialized storage chamber called a spermathecal where she keeps the unused sperm.  The stored sperm from her mating flight will last up to 4 years, after which the queen’s reign will come to an end, and the cycle begins anew.

Literature cited

  1. SASANAMI, T., MATSUZAKI, M., MIZUSHIMA, S., & HIYAMA, G. (2013). Sperm Storage in the Female Reproductive Tract in Birds. The Journal of Reproduction and Development, 59(4), 334–338. http://doi.org/10.1262/jrd.2013-038

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Filed under Breeding, Uncategorized