The Costa’s Brothers

Last September, I wrote about these two juvenile Costa’s hummingbirds who were uneasily sharing a feeder in our rose garden that hangs from a clothesline. This is such unusual hummer behavior that I thought they might be nest-mates who still shared a bond of sorts.
This week, a pair of full-grown Costa’s hummers were sharing the same clothesline and the same feeder. See the picture below. My speculation is even wilder: could these be the same two birds from last year, still traveling together and still “sharing” to the extent that a hummingbird can share?