Tree Swallows (1 Viewer)

Hi,I was wondering why my Tree Swallows were dumping their babies' fecal sacs into our neighbor's pool.Were they doing this so that they would not be detected?


Thank you

birdmeister said:

Hi,I was wondering why my Tree Swallows were dumping their babies' fecal sacs into our neighbor's pool.Were they doing this so that they would not be detected?

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Here what BNA-on-line has to say on this subject:

"Nestlings form fecal sacs that are deposited in the nest, usually into the waiting bill of a parent at time of food delivery. Prior to day 3, parents may consume feces, but later, they carry fecal sac away in their bill, often dropping it over water. . .".

That's it unfortunately, nothing being said about why the birds drop the sacs over water.

Out of interest, checked-out a few other species of swallow on BNA-online on this subject.

Northern Rough-winged. Dropped on "ground" 30-60 meters from nest.
Bank. On "ground" "several" meters from nest
Violet-green. Sacs sometimes removed, sometimes not, but no real data.
Barn. Adults "swallow or carry fecal sacs from nest"

Upshot seems to be that dropping the sacs over water--at least as a settled habit & for whatever reason it's done--is unusual among North American swallow species & may be unique to Trees.

fugl said:

Here what BNA-on-line has to say on this subject:

"Nestlings form fecal sacs that are deposited in the nest, usually into the waiting bill of a parent at time of food delivery. Prior to day 3, parents may consume feces, but later, they carry fecal sac away in their bill, often dropping it over water. . .".

That's it unfortunately, nothing being said about why the birds drop the sacs over water.

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If I was to venture a guess, I would have to say the reason for dumping it in a water source such as the pool is to mask the odor so no predators know there are nestlings around or Tree Swallows just simply prefer the water as their form of sanitation.

Sincerely,
Monique Applewhite

nikiapple said:

If I was to venture a guess, I would have to say the reason for dumping it in a water source such as the pool is to mask the odor so no predators know there are nestlings around or Tree Swallows just simply prefer the water as their form of sanitation.

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Odor masking certainly makes sense, but in that case one might expect Northern Rough-wings--another solitary nester--to behave similarly, but there is no evidence that they do. It would be pointless, of course, for colonial nesters--such as Bank Swallows--to worry about this since the status & location of their breeding colonies are obvious to predators for other reasons.