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Fat hummers (1 Viewer)
- Thread starter rseymour
- Start date
Katy Penland
Well-known member
Don't think I've ever seen a fat wild bird of any species. 
Probably just looks bigger if feathers are fluffed due to cold temps -- then all birds can look about twice their normal size.
Probably just looks bigger if feathers are fluffed due to cold temps -- then all birds can look about twice their normal size.humminbird
Well-known member
During migration, Ruby-throated Hummingbirds on the Texas coast and other species inland put on 1/2 their "normal" body weight. In other words, a Ruby-throated Hummingbird that averages 3 grams may be as heavy as 4.5 grams immediately before departure. The body fat is quite easily seen through the skin on their breast.If they do not do this in Mexico before crossing the Gulf in the spring, I understand that they have very low probability of surviving the trans Gulf flight.
I would not necessarily transfer this to non-migrant California birds though.
Mark
Bastrop, TX
I would not necessarily transfer this to non-migrant California birds though.
Mark
Bastrop, TX
Curtis Croulet
Well-known member
I've checked with my in-house hummer expert. Yes, Anna's pork up during the autumn migration season. She reports that some have had rolls of fat. There is much to learn about Anna's movements through the year. Although many areas of California have Anna's Hummingbirds year-round, they are not necessarily the same birds from season to season. There's probably some upslope and downslope movement, since we know that they abandon higher elevations where they are present during the summer, while they remain (as a species) on the coast. There may be larger-scale migrations as well. Unfortunately, our banding project has up to now lacked banding sites on the coast that would (IMHO) provide better data to answer some of these questions. This may change next year, though.
Katy Penland
Well-known member
Thanks for the fat facts, guys. I'd love to see a gordo hummer sometime and next time won't reply in such haste. :t:
I'd love to see a gordo hummer sometime and next time won't reply in such haste. :t:
Curtis Croulet
Well-known member
Katy, I don't recall noticing a "fat" hummingbird when seen on the wing. Maybe Mark or Sheri have recognized some. But sometimes it's quite apparent when they are in the hand. You can see the rolls of fat under the skin (looks like chicken fat).
humminbird
Well-known member
I have seen birds that looked "pleasantly plump", but these were usually simply birds that had their feathers ruffled either because of weather or they were trying to make themselves appear larger than they actually were IMHO. I wonder if this is not what Robert was seeing? When I see hummingbirds with fat visible through the skin, that requires blowing the feathers on the breast out of the way. I am sure that is when Curtis is seeing the "rolls of fat" on the birds as well. I think, if I am not mistaken, that Mr Rubythroat caught a HUGE Black-chinned in Christoval TX this past summer. This guy weighed in at nearly twice normal weight and he LOOKED big. This is very unusual though (they banded more than 500 birds that weekend and how many have they banded through the years and that is the ONLY one that sticks in my mind!)
Mark
Bastrop, TX
Mark
Bastrop, TX
Just an (perhaps crazy?) idea, maybe it was a female carrying an almost mature egg? Since it has been reported that nesting season for Anna's can start as soon as october, this might perhaps be the answer? It would also explain why you haven't seen this "fat bird" again...
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humminbird
Well-known member
Can't speak for Anna's, since I have never seen one carrying eggs, but in all the female Ruby-throated and Black-chinned Hummingbirds I have seen that were carrying eggs, even in the vent (where we could see them in the vent), I do not recall seeing one that I could predict would be carrying an egg because of her size. It does make sense though.
Mark
Bastrop, TX
Mark
Bastrop, TX
