Found this regarding Barn Swallows

While searching for photos to help me figure out which is the male and female of the barn swallows that came back from last year (they have 4 babies almost ready to fly any day).. anyway, found this article that is really shocking to me and very interesting if you will read the first two paragraphs.

If anyone know how to tell the difference between the male and female, i'd appreciate the info. these guys are back from last year and used the same nest. I was hoping they would make another nest and that more would come.. there are about 4 or 5 adults, probably the babies from last year.

here's that link: http://images.google.com/imgres?imgurl=http://farm4.static.flickr.com/3041/2558406540_23522ab69e.jpg%3Fv%3D0&imgrefurl=http://flickr.com/photos/84474308%40N00/2558406540/&h=313&w=500&sz=67&hl=en&start=11&um=1&tbnid=tDYKuZ_YwcLhhM:&tbnh=81&tbnw=130&prev=/images%3Fq%3Dmale%2Bbarn%2Bswallow%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN

In looking at the pair that uses my porch, it seems the female's breast is lighter. I've loved having them - they've returned for the third year) Might not be the same ones, but I like to think so. I went out of town last month thinking there wouldn't be a nest this year, and came back to four little heads peeking out of the nest! They've since fledged.

Here's what the Cornell Ornithology lab - says non attached males will demonstrate the behavior outlined in that blog. No comment on the rest of that blog entry, though. sheesh...

http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Barn_Swallow_dtl.html

You see that behaviour in alot of wild animals.

Yes - the drive to survive a tough task master.