Posted: 08/01/2016 at 16:02
Apart from the hungriness of the birds, I have noticed lots of other factors:
Some feeders seem to be able to feed at a faster rate than others - take the regular plastic seed feeders with a couple of openings at the bottom for example - the mid price ones I had could be emptied about twice as fast as the really cheap ones I got after I suffered some vandalism.
Sunflower hearts in a plastic seed feeder go down much more quickly than in a wire mesh seed feeder, even though many more birds can feed simultaneously on the mesh feeder - presumably it is harder for them to get each seed out?
In high winds some feeders will accidentally drop seed when swinging more than others - the squirrel buster is particularly bad for losing seed quickly in high winds because it essentially dispenses seeds into an open tray, with a squirrel proof shroud around. The shroud is spring loaded to the weight of a squrirrel, so if a squirrel (or big bird like pigeon or jackdaw) climbs on it slides down and covers the tray, but when the feeder is swinging in the wind, the tray is open....
A squirrel will make short work of emptying most feeders. Plastic ones they just chew around the openings to get seed faster - if you stop them doing that they soon work out how to tip them and empty them from the lids, or knock them off the hanger to do the same. I use some soft plant tie wire to secure the lids of my feeders now to combat the squirrels.
Jackdaws are another issue for me - corvids are smart so maybe not limited to jackdaws. Mine have worked out that if they can't get to seed they can swing the feeders until the seed spills out - even the squirrel buster if they can get it swinging without putting weight on the shroud!
Everything goes for fatballs, I have seen as many as 6 jackdaws or maybe 12 starlings on a small fat ball feeder ripping the balls to pieces in no time (other birds pick up the scraps off the ground) - but if there are only sparrows and tits about the balls can last for days!
Weather makes a big difference - I have seen large numbers of birds trying to get onto the feeders in windy and/or wet conditions, but they don't stick around for as long and presumably head off for shelter once they have taken on enough calories to get through another day/night?
Time of day is also a factor - here in Scotland we have short days in winter especially when it is overcast, so the birds stop feeding and head off to roost quite early and the seed lasts longer than in the spring and autumn. If I fill a feeder after about 3pm it likely won't get touched until the following morning, so if I am filling in the morning and get up late, that can greatly reduce the number of feeding hours the birds have (if the weather is good I try to fill them at night to maximise feeding hours).
I have given up with plastic feeders, too expensive if there is just one squirrel about! I have wire feeders for fat balls and peanuts (go down slowly as long as the lid is squirrel proofed), wire mesh feeder for sunflower hearts (can take other seed), and I use the squirrel buster for mixed seed, which has the mesh shroud completely protecting the inner plastic container.
I get: house sparrows, chaffinches, blue tits, great tits, goldfinches, robins, blackbirds, starlings, jackdaws, wood pigeons, collared doves, siskins (some of those just collect spillage from the ground).
And yes, in the right conditions, it is not unusual for a feeder or sunflower hearts to go in less than a day!