It can be frustrating to try to identify a species when the males and females look different… especially when the bird is named after a feature that is sported only by the male! Consider the Rose-breasted Grosbeak:
Male:
Female:
The two photos above, by the way, are by an AMAZING AMAZING AMAZING nature photographer named Jayne. See more of her photos by clicking here.
To complicate things even further, the babies often look different from the adults. Look who we caught at SWAT on closing day:
At first glance you might think, “Oh. Two females!” You’d be only half right. The bird on the left is female, the bird on the right is male. The male has slightly heavier streaking under his neck. And, if you look closely, you can see that the underwings are differently colored. The female has yellow underwings, the male red.
Ha! Switched it! Male on the left, female on the right in this photo!
Not all birds have such variety in their markings. Black-capped Chickadee males and females look alike. Chickadee babies look like poofier versions of their parents.
These differences within and between species sometimes cause problems in bird study protocols. In Project FeederWatch, for example, citizen scientists are instructed to report for each species the highest number of individuals they see at any one time. For example, if you look out the window at 7:05am and see 2 Chickadees, then again at 7:15am and see 3 Chickadees, you are to report that you saw 3 Chickadees. That makes sense, right? Two of those three Chickadees could be the same two you saw at 7:05.
Now here’s the dilemma. Suppose you look out at 7:05am and see one male Rose-breasted Grosbeak. At 7:15am you see one female Rose-breasted Grosbeak. How many do you report? You and I both know you have seen two Grosbeaks! But if you are going to follow the protocol properly, you must only report one. (If they come to the feeder together and you see them both at the same time, then you can report 2!)
To many people this doesn’t make sense. But think about it… If a male Chickadee comes to the feeder at 7:05 and a female at 7:15 – you wouldn’t know the difference, and you would only report 1. This protocol and subsequent analysis of the data takes into account the fact that some birds are sexually dimorphic and others are not.
Hmm… that was a little tangent away from Rose-breasted Grosbeaks… That’s the way my mind works!
Anyway, if Rose-breasted Grosbeaks provide identification challenges here in the east, imagine what it must be like in the middle of the continent where they interbreed with Black-headed Grosbeaks, sometimes producing offspring with mixed characteristics! Yikes!
This Black-headed Grosbeak photo is borrowed from the Flickr Collection of Noël Zia Lee. Click here to see more of her amazing photos.
Learn more:
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http://www.birds.cornell.edu/pfw/ (Project FeederWatch)
Filed under: bird banding, bird conservation, bird research, birds, nature | Tagged: Black-capped Chickadees, Count Protocols, Rose-breasted Grosbeaks, Sexual Dimorphism
It was always my understanding that you count as many ‘identifiable individuals’ as possible. To me, seeing a male and female at the different times counts as 2 identifiable individuals. But I might be wrong!
Hi Marty,
Different projects have different protocols. I’m pretty sure I’ve described the FeederWatch one accurately. For other projects, there may be other “rules”.
Thanks to Jens Birds website I was able to identify a “first fall” male rose-breasted grosbeak with it’s red underwings.
Thanks a million!