How to tell if the bird is gone from her nest?

Went to the proj about a month ago and there was a tag on the first bolt saying "Do not climb.  Bird's nest."  And sure enough I could see branches sticking out from a crack around the 4th bolt.  Just to confirm, the bird came out squawking and did a lap before slotting back into her nest above.  So we bailed.

Now, a month later, I went back and the nest is still there but no sign of the bird.  But how do I know if it's abandoned?  Some birds lay multiple broods in a season and this could run into late Summer or early Fall.  Others just one brood and out in 4 weeks.

I know next to nothing about birds, so thought I'd ask.  I feel like poking around with a stick clip pole or climbing up there is pretty disruptive, so looking for other softer methods for seeing if she's still there before climbing.

(This is in Clear Creek Canyon near Golden Colorado.)

Love your question, as a bird nerd, respect for even asking.

Oftentimes not just her who rears the chicks but a male as well. Depends mostly on family, less species (think wrens vs gulls). 

You’re also totally right about multiple clutches, very possible. House Finches (the generic songbird in most western urban areas) have something like 5-6 clutches a year. Big raptors have just one. 

There’s species that won’t be disturbed by you at all. Hell there’s a violet-green swallow who lives in a jug/hueco on the Glitz (the glitch?), whatever’s right of the Gift at the second pullout. Countless other examples of nesting avians that won’t care at all.

There’s also species you’d be better off jamming really hard with your stickclip and getting rid of said nest (Euro Starlings for example, though it’s unlikely one of those, or Rock Doves (normal pigeon)) as they’re invasive as all hell.

With the bird being ‘gone’ hard to ID species. Though most songbirds/other smaller species won’t abandon nests if disturbed, I’ve picked up yellow warbler eggs and put them back in the nest to be reared just fine. Someone else will prob try and force a more conclusive idea but in terms of bird info and anecdotes that’s what I got! 

The bigger question should be, "Why is there a bolt next to a crack?"

ginger wrote:

Love your question, as a bird nerd, respect for even asking.

Great answer, Ginger!  I'm not quite a "bird nerd" but I've experience with them on cliffs (banding eagles, setting up rappels to Peregrine nests, etc.), in addition to encountering them on climbs, and your attitude is right-on in my opinion.

John, you said the bird flushed and flew around on your first visit.  Any idea what kind of bird it was?  Most nestlings have fledged by now...

Todd Jenkins wrote:

The bigger question should be, "Why is there a bolt next to a crack?"

Only a bigger question for a smaller mind.

John Byrnes wrote:

Great answer, Ginger!  I'm not quite a "bird nerd" but I've experience with them on cliffs (banding eagles, setting up rappels to Peregrine nests, etc.), in addition to encountering them on climbs, and your attitude is right-on in my opinion.

John, you said the bird flushed and flew around on your first visit.  Any idea what kind of bird it was?  Most nestlings have fledged by now...

My guess is it was a cliff swallow, but I'm not expert enough to be sure.

Todd Jenkins wrote:

The bigger question should be, "Why is there a bolt next to a crack?"

Not all cracks are suitable for gear (imagine a large flaring crack, say 20cm in width, which is where this bird's nest is).  Moreover, the crack in question is pretty far off the line of weakness, so even if it could take gear, it's not clear if you could get over there to place it.

But in Clear Creek, even if there were a perfect placement right on the bolt line, there would still be a bolt.  Because there are very very few mixed routes there: it's either trad (all gear, good placements all the way), or sport (all bolts).  Matt Lloyd once did Anarchitect (12d on bolts, probably harder on gear) using questionable pro, and running it out a bit, but he did it (headpoint style, rehearsing the moves using the bolts, then doing it on gear).  Rob Daniel did Hungry Wolf (13a) on gear after rehearsal, but 99% of ascents clip the bolts ( vimeo.com/461606445).  

A lot of these climbs would never get done if people had to do them on gear.  A lot of uber classics in Eldo never get done because they're 5-stars but 5.12 X on RPs.

John RB wrote:

My guess is it was a cliff swallow, but I'm not expert enough to be sure.

"The young hatch at about 13-15 days and fledge at about 23-26 days, though remaining dependent on the adults for another several days."

https://www.birdzilla.com/birds/cliff-swallow/

So it's very likely that the nest is empty until next year.

This one is for Ginger and eventually (Fort Collins) John.

What do you call a pair of crows?
Attempted murder.    

Could be a cliff swallow, but almost just as likely a barn swallow or a violet-green swallow. The names are less indicative of nesting site than they’d seem.

That or a white throated swift, they’re pretty distinctly different from swallows if you look up pictures (the tail, colors, and general size are different). 

All those swallows and swifts are pretty damn tolerant of humans. You’d be surprised how many routes have birds from those families living on/in them!

Todd Jenkins wrote:

The bigger question should be, "Why is there a bolt next to a crack?"

And maybe a bigger question would be why ya can’t enjoy the bird talk or answer that question yourself.