Do bushtits grieve?

This is really part of a much larger, controversial, and more philosophical conversation that should be had at some point....but most certainly won't grace the pages of this blog.  Nonetheless I do think it's worth a brief mention here:  

There's a fine line between empathizing with your study species and out-and-out anthropomorphic interpretation of animal behaviors.  It's a line that's not easily drawn when you've spent as many years with one species as I have ---- even if that species is only a tiny drab-grey bird.  

But I do think it's important to point out that, as a behavioral scientist, I firmly believe that animals have emotions comparable to our own.  Why do I think so?  I do so for a variety of reasons.  First, we share the same functional responses internally to similar external stimuli.  Danger releases adrenaline, causing us to behave appropriately to that lion we've just encountered.  Run!  (or fight!) Prolactin is released at the sight of babies.....or nestlings.  It's why my hollering baby didn't get thrown out with the bath water.  And it's why birds feed their begging nestlings.  I could go on and on.  Suffice it to say that we all share the same chemicals causing us to behave appropriately -- thereby surviving and, eventually, reproducing. 

That's the functional angle.  But what about feelings?  I have always tried to convince my students that feelings are what we feel when we are flooded with those chemicals.  They are what cause us to react as we do.  If you get injected with adrenaline, you feel fear or anxiety.  If you are injected with prolactin, you feel a warm glow.....nurturing and patient.  I'm being simplistic, but I think you may get my point. There is no reason not to believe that a bushtit loves its nestlings any less than I love my own children.  Love causes us to put up with parenting.  And parenting passes on our genes.  

Which brings me to the subject of today's blog:  Do bushtits grieve?  

I believe they do.  And, of course, I have a story to illustrate my point. 

One of the nests in 2018 on Reed campus was found in March --- early in the season.  It was just on the water's edge deep in "The Canyon" and was found by Gary Granger.  By the time I saw it, it was almost finished and stood out starkly against the sky and water.  It was built well into some very tall grasses and reeds, but was not cryptic at all.  In fact, it was a very obvious nest.  

Being obvious doesn't seem to doom bushtit nests.  Many that I feel are fated for destruction because "how in the world could that jay over there not see that ridiculously obvious bushtit nest??" survive just fine.    Others that seem carefully hidden -- so much so that they are practically impossible for us to watch -- are torn to shreds within hours of hatching or even earlier.  So being out in the open couldn't predict this nest's final fate. 

The attendants were an unbanded female and a banded male (LGXL).  They seemed a happy couple, bringing feathers to the nest fairly frequently and not nearly as noisily as some.  I had fond hopes the nest would survive and produce a batch of healthy fledglings. 

Eventually it was clear that they were incubating eggs.  The unbanded female and LGXL had became furtive and silent around the nest, exchanging incubation duties with only a quick "spit" to alert the incubating bird to its replacement's arrival.  A quick, almost imperceptible, exchange and then silence.  (This is why watching incubating nests in positively maddening.....they switch so quickly, it's hard to read bands.) 

One day, however, I arrived for a watch only to find the nest in tatters.  Feathers were everywhere.  It had clearly been someone's lunch and the contents were now digesting in someone's belly.  In most cases, when I come across a destroyed nest, the parents are no longer in sight.  They have taken off to begin a new nest or to try to kick a neighbor out of theirs.  But that day was different.  LGXL was there alone --- there was no sign of the unbanded female. The sky was dull and the gentle wind ruffled the scattered feathers, sending them further from the now defunct nest site.  

LGXL seemed listless.  He was silent and hopped slowly around the area.  Several times he dropped to gather a small feather and bring it up to what remained of the nest. Once there, he hopped slowly about a bit and then discarded the feather only to try again a few minutes later.  His entire aspect can only be described as "dejected."  He spent some time perched on a nearby branch, puffed and silent, and then began his random and pointless feather-gathering once again. 

It was hard to watch, what can only be described as, this sad, little bird.  He seemed so lost and lonely.  Usually when a bushtit gathers feathers, they are quite animated and noisy.  I would  describe it as a "joyful" time.  Not so this quiet, listless gathering of lost feathers and bringing them to the lost nest.  

I thought at the time that LGXL was just there soon after the predation had occurred and that this might explain his unusual behavior.  I also wondered if he had lost his mate as well to the predators.  That does happen, although rarely.  I watched for awhile and then left him to continue in solitude.  I fully expected him to be gone the next day.  

But he wasn't.  He was still there.  He wasn't quite as focused on the nest as he was the day before, but he was still hopping about slowly and occasionally picking up a feather only to set it down almost immediately.  After awhile, he seemed to give up and fly across the canyon to join a known pair who were foraging on the other side and whose nest I hadn't located yet.  It was just the 3 of them, making me even more certain LGXL's mate had perished along with the nest.  

Over the next week, I saw him near the destroyed nest site a couple of times, but for only brief periods.  It was as if he returned once in awhile in the vain hope that the nest and his mate was still there.  

As far as I knew, he never found another mate.  For the rest of the season, I saw him rarely and only alone or in the company of a small flock.  The following year, he was gone -- presumably he had died over the winter.  

So that's the story.  Make what you will of it.  It's hard not to imagine LGXL wasn't grieving his loss -- and for more than a single day.  Imagine his plight.  One day he was incubating a clutch of eggs in his warm, safe nest, switching incubation duties with his mate, and cuddling up with her and the eggs every night.  Then suddenly it was all gone.  No eggs.  No nest.  No mate.  It makes sense to me that he would be grieving --- and his grieving behavior wasn't particularly productive.  It didn't help him.  It was depressive.  He didn't find a new mate.  He didn't rebuild his nest.  

For what it's worth, I think he really was a sad little bushtit.         

   

 

 

 

If at first you don't succeed......

 ......try, try again...and again, and again....ad nauseum

In Arizona, a nest failure often resulted in intense competition for neighboring nests within the same flock. Sometimes the interlopers were successful at booting out the residents.  Sometimes they weren't.  When they were, the original residents were faced with their own nest-less dilemma and went off in search of a handy nest nearby to try to takeover.  When competitors weren't successful, they tried elsewhere or finally built their own nest.  Sometimes they reached an uneasy truce with the residents and joined the nests as "helpers."  But in almost every situation in which a nest was lost, the homeless pair would at least try to take over someone else's nest first.  

Not so in Portland.  Although I do see competition for neighboring nests on occasion, most pairs who have had their nest torn to shreds by a predator and the contents devoured, seem to move right into building their own real estate.  

One, rather extreme example from 2021 immediately springs to mind.  It involves a female on the Reed campus banded as RREX (roar-ex) who now holds the record for number of nests built in a single season.  We suspect she was a SY female (hatched in 2020) based on her behaviors and choice of nest sites early on....none of which served her well!  A supremely inexperienced bird perhaps.  

RREX's first nest (RD-3) was in the same place as a 2020 nest in a pine over-hanging a busy walkway on campus.  It wasn't very cryptic.  Nonetheless, she and an unbanded male (UnbM) managed to hatch a brood of chicks....which were eaten and the nest destroyed only 4 days after hatching.  Ah well.  

Just a day later, RREX and UnbM were pilfering nesting material from the remains of a neighboring nest that had also met the same fate and were well on their way building a new nest (RD-29) just a few yards from the one supplying nesting material (thrifty birds!)  in the same tree high in the lofty branches if a huge pine.  Dumb move, RREX.  Um......maybe the destroyed nest should have been a clue???

Only a few days into that rapid build, RD-29 was destroyed, likely containing eggs given that it was almost complete and RREX and her mate were ready to go, so to speak.  

Score ----  RREX 0: Predators 2

But RREX was not deterred!   On the day we found RD-29 in tatters, RREX was again building yet another nest (RD-34).  This one was built in record time, reaching an almost ready state in just a day.  It was small and shoddily put-together, but seemed to suffice because -- you guessed it -- 3 days later it was also history.  

Score --- RREX 0: Predators 3

Was RREX done yet?  One would think so.  But, no, she was wasn't.  Her 4th nest nest was found that same day.  This time it was up against a building in a small deciduous tree and was very well-concealed.  Maybe she had learned a lesson?  Nope.  Four days later, it was nothing but a lump of spiderweb, feathers, and lichen on the ground.  

Score:  RREX 0; Predators 4

At this point we were in wonder at this plucky little bird.  She seemed determined to build a nest that would survive the season, no matter how many tries she had to make.  And so that same day.....

.......we found RD-40, which progressed very rapidly.  This time she had placed the nest in one of the most least cryptic places imaginable.   It was in the top of a bush right next to the entrance to the Psychology building.  It was extremely obvious but, perhaps somewhat protected by its people-heavy location.  Or so we (and she?) hoped.  But, alas, it was not to be.  After a few inactive, but hopeful, nestwatches, I discovered a hole near the top of the nest.  Apparently predators had come in and removed the contents without destroying the nest.  It happens.  

Score:  RREX 0: Predators 5

That's a record.  I have never seen so many rebuilds, and so rapidly begun, by the same bird (we assume the same pair even).  It not only emphasized the dramatic predation rates we were seeing in Portland in 2021, it also flew in the face of my early assertion, based on Arizona birds, that failed breeders attempt a takeover if they can.  RREX apparently never did.  

So what happened to her eventually?  Well, just a day or two after I ascertained that RD-40 was toast, I did see her in the vicinity being actively chased and courted by 2 males at the same time.  So she was still a hot commodity and still interested in nesting.  There even might have might have been a Nest#6 (or even #7) somewhere.  But we will never know.     

But I do know she was still around in the fall.  I found her in a massive flock one day among many other  banded birds on Reed campus.  The next day she was the only banded bird in a flock of about 10.  They were making a leisurely loop taking in some of the nesting areas RREX had used that spring.  Could it have been RREX and her (finally) kids?  

We'll never know.     

 

TOTX

Sometimes someone sends me a photo so stunning, I can't help but share it.  Today I'd like to post this beautiful photo of TOTX (tots) taken by Tony Freixas.  Thank you, Tony!  

Since we have his picture, I'll tell you a bit about TOTX and his life this year.  It was a difficult one but also very interesting and intertwined with the lives of his neighbors.  

TOTX originally had a lovely nest (RD 2) in a backyard immediately adjacent to Reed campus.  It was found during the last week in March in a very early stage and was low-hanging fruit, nestled in a thick vine just a few feet off the ground.  Nonetheless, it was hard to watch because a tangle of thorny berry bushes grew up along the border of the garden and campus so that short people (me) had a very hard time seeing over and into the yard.  Fortunately, the owners of the yard generously allowed us in to watch the nest and all was well.  We even had a chair to sit in.  A nice perk.  

But TOTX was a bit of a pain.  He was a very noisy bird.  Not only was he noisy near the nest, he was noisy no matter what.  We could always tell he was in the area and exactly where he was with his mad spitting.  And he wasn't just spitting at us.  He was spitting at the world.  The female (who remained unbanded) was much more discrete when she arrived alone.  But TOTX was often found following her about noisily, during nest-building, egg-laying and even after the kids had hatched. I don't know how she put up with him.  

TOTX's loud personality eventually got him in trouble about 10 days after his eggs had hatched.  Predators finally got the hint and found his nest, ripping it to shreds and undoubtedly feasting on the contents.  End of RD 2.  But not the end of TOTX (and, we assume, the female he was with).  

Just 2 days later he was seen visiting at the nest of his closest neighbors (RD 24) only 50 meters south of his destroyed nest.  The residents, PXPW (female) and ERYX (male) had built their nest also unusually close to the ground...about 6 feet.  It was pretty obvious hanging in the dense shade between two very large pines.  Its saving grace, however, was the vines and low branches that also hung around the base of these trees so that the bird's comings and goings were not too obvious.  During this visit, TOTX just hopped about and peered in.  PXPW and ERYX seemed unperturbed.  No fuss.  Just a friendly and quick perusal of the neighbor's real estate.   

However, only two days after TOTX's first visit to the nest he was found visiting again.  This time things were very different.  ERYX was nowhere to be seen.  TOTX, an unbanded female, and an unbanded male were all there making a fuss around the nest where PXPW was incubating eggs.  The unbanded female was ripping nesting material from the nest and the unbanded male was trying to court poor PXPW.  It was all very puzzling.  Where was ERYX?

Well, it turns out that, unbeknownst to us at the time, ERYX had found an unbanded female (perhaps the nest-material thief at RD 24 and even perhaps the female at RD 2) and had been building a new second nest (RD 41) not far away.  In fact, it was almost complete by the time we found it that very day.  ERYX had apparently abandoned  PXPW to incubate on her own while he established a new nest with a new female.  Yet another bushtit cad!   

Important note:  We don't know who the female at RD 41 was as she was unbanded.  She may have been TOTX's mate from RD 2.  Or she may have been just another unbanded female.  We will never know in part because......

.......just 2 days later TOTX was visiting RD 41.  In fact, TOTX, PXPW, ERYX, and an unbanded female were all there together.  This time TOTX and ERYX were aggressively chasing each other and TOTX was observed entering the nest repeatedly.  Just two days after this TOTX and an unbanded female were clearly victorious and were the proud new owners of RD 41.  ERYX was now back at RD 24 with PXPW, vanquished and again a dutiful dad, helping her incubate and feed once the nestlings hatched.  

All seemed well for TOTX and the unbanded female at RD 41 as well.  They finished building the nest which was well-hidden in a hanging branch of a very high deciduous tree about 15 feet over a sidewalk.   Both birds were very careful in approaching it.  TOTX seemed to have learned his lesson and was not the noisy idiot he had been at his first nest.  The nestlings hatched and we were anticipating getting up to them soon for banding and blood for DNA until......

.......disaster struck in the form of the heat dome.  RD 41 was one of the casualties -- all the nestlings perished.  It was sad for us and undoubtedly sad for TOTX as well. 

But, happily, he survived.  The picture above that was taken in the winter attests to that.  Hopefully we will see him again this spring with a brand new nest.    

  

   

Thoughts on bushtit numbers after the heatwave

I've noticed quite a bit of conversation in OBOL re the heat dome and resulting bushtit numbers.  Rather than comment in OBOL, I thought I'd offer my thoughts here so that a larger audience can see them if they want.  These are just thoughts.  I have no answers! 

First, every single banded adult at the eight nests survived the event. So, at least from that small sample, there wasn't any adult mortality.  In addition, many other banded birds have been seen since.  I'll have a better idea of adult mortality when the breeding season begins next month.  But even then, I won't know the cause if the % survival is lower than usual.   

We have found about 100 nests/year over the last 4 years in Portland.  I have never had a nest with dead nestlings before.  The only other time was just once in Arizona after a freak cold spell: 3 out of 4 banding-age nests contained dead nestlings.  The only surviving brood had 3 adults feeding at (and sleeping in) the nest.  

On the other hand, predation rates were exceptionally high this year in Portland.  Personally, if there is a dip in bushtit numbers, I would expect that had a greater effect on the population than the heat dome, given that the heat came very late in the nesting season.  

Bushtit numbers in the winter are hard to come by.  As they are in large and mobile flocks, you either see them.....or you don't.  Many CBCs miss bushtits.  But that doesn't mean they aren't there!  I think the best way to get an indication of the robustness of a population is to count flock size.  Not estimate.  Count.  That means catching them as they cross a street or from tree to tree and counting them as they cross.  Big flocks in winter=healthy population.  

The problem is the occasional small flock doesn't mean much.  This November and December, I found the same bird in both a monster flock of >50 and messing around for over an hour in a smaller flock of 10.  So....she's was doing both.  I think if you go out often and see only small flocks of <15 birds, that may indicate a problem.  

The heavily-feathered bushtit nest is great at insulating against cold.  But it also serves to protect against heat.  I did a short study in AZ several years ago and found that the interior of a bushtit nest stays at a reasonable temperature even in full sun on a very hot day when the exterior nest surface temp rose above 120 degrees.  In Portland this year,  WT 12---the 3-bird nest that lost all 6 nestlings during the heatwave---was a small nest with very little insulation.  It was mostly in the shade, BTW.  The one nest with eggs during the heatwave was a pretty bizarre nest (the 3rd nest for the pair that year) with uncharacteristically thick sides and many feathers.  Perhaps that saved it?  Who knows.  It was also partly shaded as were most of the nests at that time.  

One more point:  Nests that survived were  significantly closer to water.  Water is essential to prevent dehydration which is the primary cause of death in the heat for birds.  We (Amit Gordon, Ian Connelly, and I) wrote all these observations up for publication and it is currently in press in The Wilson Journal of Ornithology.   

Hope all that is of some interest!  Comments and additional ideas welcome.  

What is it about bushtits??

I am often asked "what's so interesting about bushtits?"  The answer to that is "it would fill at least one long book."  And I am in the process of writing it.  In the meantime, I thought some of you may be interested in seeing a very brief list of some of the odd, uniquely bushtit, behaviors I have seen.  

First you need to know that bushtits live in tightly knit family flocks of from 10 to 15 birds that combine with other flocks as the breeding season winds down.  During the winter, flocks became hard to find because they travel over several flock home ranges. Combined winter flocks may be huge.....even this year after the heat event, we often ran into a flock on Reed campus that had at at least 50 birds, some of whom were old friends of ours.  

The family and extended family flocks are maintained throughout the breeding season.  And that's what makes bushtits truly unique.  Although pairs (or more than a pair) maintain a weakly defended area around the nest, flock members frequently visit each other's nests and hang out when not at their own nest. They all know exactly where all the flock nests are and who is where and what they are up to.  They even seem to have "best friends" or birds they are seen with frequently and nest near.   

That's the skeleton version as there's much more complexity to the story!  But it's enough for now.  Here's some of the fun stuff I have seen over the years.  Teasers, as you will.  BTW, none of these observations would be possible without color-banded birds.  

1. Musical nests (nest ownership exchanges -- and back):  One day XXXX and YYYY will be building at nest and the next day they are nowhere to be found.  Instead it's ZZZZ and WWWW.  Sometimes XXXX and YYYY may return, and ZZZZ and WWWW will be building a new nest elsewhere.  I'm not the first one to observe this.  Steve Ervin did as well in CA in the early 70s. But he wasn't focused on that aspect of bushtit behavior so he didn't follow up on it.  

2.  Bushtit cads:  Males who cavort with a neighboring female even while he has a nest elsewhere.  I've detailed one situation like this from last year.  There are more.  

3.  Deadbeat dads:  Males who not only cavort, but takeover a nest while their first mate handles incubation alone (both male and female usually take turns).  They then desert the 2nd female to return to being a dad at the first nest, leaving the 2nd female to fend for herself.  

4.  Extra birds ("helpers"):  These are usually males and usually there's only one.  But it varies; in AZ I did have one nest with 6 males and one female. There's a good story in that re how and why this happens!  Hint: is it really helping.....?

5.  More than one pair at a single nest:  two males and two females have been observed.  More on those complicated stories later.  

That's a smattering of the convoluted shenanigans bushtits can get up to.  They seem a cheery and cooperative little bunch, don't they?  But I believe it's actually competition that drives the system.  At least that's what I think as I learn more about them over the years.....stay tuned!       

The deadly heatwave of 2021

No recap of the 2021 bushtit field season can fail to omit the effects of the unprecedented heat wave on bushtit nestlings.  And it wasn't good news.  It was, in fact, quite sad.  And informative.  Unfortunately.  

In late June, a "heat dome" settled over the Pacific Northwest for 3 interminable days.  It was record-setting and completely out of the range of normal for the area.  Completely.  Each day the temperature climbed.  By the 28th of June it was 116 degrees in the shade.  Walking to the grocery store from my house -- only a 5 block trek -- felt risky.  My daughter, her partner, and their cat joined us in my 800 sf house which we tried to cool to barely acceptable with 2 ACs.  Even so, we had to partition the house into one small space, leaving the rest of the house to bake.  We all became vampires...avoiding the day and going out only at night for "fresh" 100 degree air and short strolls around the neighborhood.  

But what of the bushtits?  How were they faring?  It was the tail end of the field season and we had only 8 active nests.  One of them was close to fledging age.  One was still incubating.  The other 6 had nestlings....some very young, some older.   One of these was a nest (WT 12) we were particularly interested in as there were two males and one female.  All three birds had built and incubated and were now feeding.  We were, understandably, anxious to get blood samples from the nestlings once they were old enough.   Were both males co-dads??  It seemed highly probable.  So that was the only nest we kept tabs on for those 3 days.  One of us would head out at dawn, watch it for 30 minutes in the 90 plus heat, and then crawl back into whatever cool cave we had devised for ourselves to wait out the day. 

By the 29th the heat had abated somewhat so we set out to check the 8 nests we had.  I won't get into the all the sad details of what we found.  I'll just summarize:  

One nest had been torn apart by predators, the contents most certainly devoured.  That's not unusual.  Another had fledged prematurely and a grisly fledgling corpse was hanging from the entrance -- sans eyes and brain -- apparently entangled in the artificial poly the parents had used to line the entrance.  Ok.  Gross, weird........and huh???

Two others were silent and when we opened them, contained dead nestlings.  The adults were no longer even in attendance.  (We did, I might add, relocate every single adult with an active nest during the heatwave and could verify none of them had perished from the heat.)  

Happily, 3 nests had survived:  one still had eggs and the other 2 were feeding kids, although we were to later discover that only some of the nestlings had survived in each.  And only one egg hatched from the nest with eggs.  So even those nests had not survived unscathed.   

By far the saddest result of the heatwave was at WT 12 -- the nest we had such fond hopes for.  When I arrived to watch it at 6am on the 29th, all 3 adults were bringing food to the nest.  That was encouraging!  But it didn't take long for me to discover the sad reality.  Yes, they were bringing food in, but they were also bringing it out.  It was clear that whoever was in there was no longer capable of eating.  But could they still be alive?  I rushed home to get some sugar water thinking that a bit of that might revive the nestlings and save their lives.  (Bad science, but sometimes I just can't help it.) But, alas, when we opened the nest we found 6 tiny dead perfect nestlings....smaller than they should have been for their age.  They must have died not long before given the behavior of their parents.  So sad.  We collected the little bodies to take samples from the livers for DNA. 

As we encounter more of these catastrophic heating events, most certainly due to human-mediated global climate change, local birds and other animals will no doubt be affected as were the Portland bushtits.  In fact, it's highly likely that other breeding birds were impacted in a similar way during the 2021 heatwave.  It was only the fact that we were already closely monitoring bushtit nests, and have been for many years, that we were able to observe the effects of the heatwave on them and compare that to previous years.  

A sad end to the season and an ominous warning for the future.              

   

Blogging woes and bushtit funny business

I am a bad blogger.  I will readily admit that.  I start the field season fresh and enthusiastic and fizzle out as the season progresses.   I have a pretty good excuse:  as I find more and more nests (about 100 each year the last 3 years) I get side-lined into my research and am too exhausted at the end of the day to sit down and write about all the cool things I saw.  If I could clone myself, I'd be in business.  But that's not happening.  

So, once again, the bushtit breeding season looms and, once again, I am faced with the excitement of sharing the excitement----and the reality that I will do a pretty bad job of it.  Ah well.   

In this lull before my 2022 research in Portland and during my sojourn in the New England winter,  I'd like to share a few highlights from last year's bushtit research that never made it into the blog.  

The first is what was happening at Nest 28 and Nest 20 near the border between Sellwood Park and Oaks Bottom.  

Nest 20 was in a monster pine tree on a very (very) steep slope.  When we first found it, it was being built in the "lower" branches  (30 or so feet up) in almost the exact location as nests in 2018 and 2019.  Same branch.  Same awkward position for watching.  The builders this year were W-X -- a male who hatched nearby in 2019 and was rebanded as WUUX -- and an unbanded female.   WUUX had been around in 2020, and we assumed he had a nest somewhere, but we never found it.  His sister (also originally W-X) nested that year in a tree not far from her natal nest as well.  (That throws a bit of a monkey-wrench into my assertion that females don't hang around, but disperse.  I'll just ignore that for the moment...).

[BTW, both W-X female and WUUX were kids of PYLX who, if you've read some of the earlier posts, you may recognize as the second male at Nest 11 in 2018.]  

A week after finding Nest 20 we found Nest 28 in a pine over-hanging a very steep slope just on the edge of Sellwood Park near the parking lot.  It was almost finished and was being built by an unbanded male and a female (eventually banded as XYYY and XEEE).  It was about 200 meters east of Nest 20.  Not far. But not all that close either.  

Neither nest was in a particularly favorable position for climbing up and banding the nestlings, so we put them both in a low priority category and watched them infrequently until.......

......very interesting stuff started to happen. On several watches (which later turned out to be during egg-laying when the female mates) WUUX showed up at Nest 28 chasing and following the female relentlessly while her male sort of fluttered around after them. WUUX even visited the nest several times...peering in and then taking off again after the female.   This would go on for over an hour and seemed to be almost a daily occurrence for a week.  WUUX was still seen at his own nest on and off, where that female was also laying eggs.  (It certainly does beg the question:  what was the female at Nest 20 doing while WUUX was off dallying with the female at Nest 28?  Huh.  Interesting.  While the cat's away....??)

After a week of this foolishness, WUUX was back at Nest 20 behaving as a dutiful dad: sharing incubation duties with the female until the eggs hatched and they began to feed the nestlings.  Which is when Male #2 (banded as RRRX) showed up and began to help.  Because of the difficult position of the nest, we weren't quite sure when he arrived but by the time we did see him, he was merrily feeding as if he belonged there.  And WUUX was perfectly fine with it.  

Because of WUUX's frequent visits Nest 28, in particular, suddenly became a nest of great interest.  Was it possible that the nestlings that eventually hatched were not just those of XYYY?  Was it possible that WUUX has also managed to mate with XEEE and was therefore also a dad there?  It seemed very possible.  And now that it was possible, we needed to get to those kids and get blood samples for DNA as well as blood from both XEEE and XYYY.  Remarkably, we already had WUUX's blood from when he was a nestling.  I say remarkably because in most cases where there is an interloping male chasing a female at a nest, he is unbanded and we have no idea where he came from. And we never get his blood for paternity analysis.  So this was a golden opportunity.  We think we know what WUUX was trying to do.  We know when he was trying to do it.  And, most importantly, we know who he is and we have his blood already.  

Perfect.  As long as we can also get blood samples from the parents at Nest 28 and from the kids we would know if he had been successful.    

But that nest.....Nest 28.......it was a challenge.  It seemed a risky business to climb up to it.  Nonetheless, we were determined.  We dragged in a long, heavy ladder and found 2 limbs close enough together to lean it against at an awkward angle of maybe 20 degrees.  I crawled up very cautiously and looped a rope around the branch the nest was on and pulled it carefully towards me.  This is when a hanging, enclosed nest is a big help.  No matter how much it swings or tilts, those kids can't fall out.  

No problem.  We got to the nest.  But the kids were a few days too young. In the end we had to wrestle the ladder back down and up again twice before the nestlings were "ripe."  Then it was a simple matter to band them and take blood samples.  

That same day we successfully banded the kids two of us stayed behind and set up a net to get samples from mom and dad.  This was also a bit of challenge because there was no good place to set up the net.  My assistant finally sat under the net with tape of begging nestlings and the male magically hopped right into the net and we had him.  Right before the nest fledged, we got samples from the female too.  Eureka!   A "complete set!" (says the vampire).  

Now I also think it's very possible that RRRX was a father at Nest 20 along with WUUX, especially since WUUX was frequently absent and misbehaving at Nest 28.  But we'll never know because that nest was truly impossible to reach.  We did, however, get a blood sample from RRRX and hope to find out later if he is somehow related to WUUX.  That's yet another possibility......that males who show up to help are helping close relatives.  

We shall see....only the DNA holds that answer. Until then, the mystery remains a tantalizing mystery.   

   

 

The Attack of the Killer Goldfinches

Ok.  I admit that's bit dramatic and over the top but, honestly, there is something up with goldfinches and bushtit nests this year.  Let me explain:

Goldfinches don't build quite the elaborate nests that bushtits do.  Goldfinch nests are basically a cup fashioned with sticks and grass stitched together with.... spider web.  Unfortunately bushtit nests are a handy source of spider web since it (along with lichen) is the primary building block of the bushtit nest, allowing it to be stretchy and strong at the same time.  Every year I do get goldfinches attempting to pilfer material from bushtit nests.   Often the bushtits fend them off.  But sometimes they just can't.  Usually this interest by goldfinches is short-lived and peaks around the time bushtits are building their first nests so they can repair the damage.  After that, goldfinches have usually lost interest and are minding their own business.  Usually.

I already knew that goldfinches can have quite a dramatic and negative effect on a bushtit nest.   Once, in Arizona, I found a bushtit nest (after a laborious and exhausting search of several hours) in the building stage that was being constructed by a happy little pair.  The next day I came back to find a goldfinch ripping off material faster than the poor bushtits could bring it in.  And they didn't even seem to notice.  By the following day nothing remained of the nest and the pair had disappeared -- presumably to find a safer neighborhood.

Here in Portland I have seen goldfinches removing nest material from bushtit nests, but it rarely seems to effect the integrity of the nest.  Sometimes the nest looks a bit "fluffy" afterwards, but it survives.

Not so this year.  This year the goldfinches have gone mad.  I don't know if the unseasonably cold and rainy May has forced them to be more aggressive about stealing spider web from bushtits or what.  Perhaps they are rebuilding lost nests in record numbers? Regardless, they have caused devastating consequences to some of the nests I've been following.

One nest fledged a first brood successfully and was incubating a second when the goldfinches removed enough of the neck of the nest to cause it to be abandoned and then fall to the ground.  Another nest with only 10 day old nestlings (they fledge at 18 days) is just hanging by thread and a hole has been torn into the neck such that the poor nestlings are essentially in a hanging cup nest -- open to the elements.  I expect it to fall and the nestlings to disappear any day now.

Still another nest was close to fledging their first brood and the goldfinches removed enough material to cause it to fall, leaving the nestlings on the ground and easy pickings for the predators that doubtless devoured them that night.  Finally, I have far more bushtit nest starts that get to the "hanging sack" stage and then are abandoned as threadbare and forlorn wisps.  They have been stripped of their material by.....goldfinches.  

I thought nest predators were the bushtits' worst enemy.  Who would have guessed that this year it would be goldfinches?



 

The carnage begins

Nests are hatching already in spite of the cold and wet spring.  Interestingly, by far the greatest percentage of nest with nestlings is in Westmoreland Park.  Next is Reed campus.

But that's where the carnage is happening.  Alas, we may be following the same pattern I observed last year when the percentage of nests lost at Reed due to predation was about 80%.  In comparison, Oaks Bottom and Westmoreland nests were relatively safe at 12% losses. In 2018, Reed also lost few nests at 11%.

So what's up with Reed?  Well, my working hypothesis is that crows, being exceptionally smart and opportunistic, figured out that bushtit nests are lovely little parcels of protein and cue in on them just as they hatch and activity increases as the parents go to and fro with food for the kids.  In 2018, they were relatively clueless. It was last year that some individual crows figured it out.  I was hoping they would have forgotten.  But, so far, it appears they may have long memories.

Of course crows are not the only predators on bushtit nests.  All the corvids (jays, crows, and ravens) as well as squirrels and other mammals that can climb trees are happy to enjoy a meal of baby bushtits.  Owls may also pick off nests at night.

So it may be that Reed has a habitat that encourages populations of other predators besides crows.  But that doesn't explain the difference between 2018 and 2019, does it?   Only a predator that has learned about the delectability of bushtit nests would explain that.

My money is on the crows.

Regardless of the perpetrators, Reed campus is a frustration as nests that were lovely and easy to watch and reach eventually to band babies at are found torn and useless.  In every other way, Reed campus is the ideal study area this year.  Because of the current pandemic, there are few students and visitors on campus.  Campus security is out in force.  I can walk around, for the most part, without a mask.  It's really an ideal research site in these unusual times.  The rest of my study areas are crawling with people on nice days.  And, since nice days are unpredictable, I can't depend on being able to be out safely.  This is particularly true of Oak Bluff trail where joggers and walkers are impossible to distance from.  Consequently, those nests (and there are plenty!) have become very low priority.  This is extremely sad because that's the most "natural" area I have and I have always enjoyed my interactions with the people I meet there.

Oh well. This too shall pass.  In the meantime, we are doing the best with what we have and are keeping our fingers crossed that a few Reed nests survive the season.  

LLRX loses and a surprise

Poor LLRX.   Remember him?  He was the male that cruelly abandoned his mate to raise the kids on her own in 2018 while he did who-knows-what.

Well, the first nest lost this year to predators was his.  We found it early in March on Reed campus not far from his nest last year (also lost to predators).  High in a tall cedar, it was fairly cryptic although a bit hard to watch because of the distance.  LLRX and the unbanded female he was with were dutiful in their nest-building activities.  Things seemed to be going well.  The nest looked finished.  But, alas, the area is crawling with cawing crows and I believe (not know) that they were the culprits.

At first we thought our eyes were deceiving us and we just couldn't see the nest.  But 30 minutes of searching and finding no nest where it used to be along with hearing no bushtits, and we were sure it was gone.  We did finally find the remains (how gruesome that sounds!) on the ground near the tree.  It was torn to shreds with no evidence of what it contained:  no eggshells, for example.

Worried about LLRX (sometimes adults are also taken) I played my favorite bushtit tape and he came roaring in right away, sptting like mad.  He may have lost the battle, but wasn't going lose the fight!   I expect to find his new nest soon.

On a more cheerful note, a nest we had given up as abandoned mid-build, has been re-occupied!  We found a pair madly building there the same day we lost LLRX's nest.  A nice surprise.

Lose one.  Gain one.  An even exchange.

Bushtit crazy time

It's that time of year.   Nests are mostly complete.  Some birds are egg-laying and incubating.  But it's not nearly that simple.  It's time for the friendly little bushtit to become not so friendly to their flock mates.

Today I saw a couple of good examples of bushtits mis-behaving:

The first was at a lovely nest over-hanging a creek.  It was finished quite some time ago, being built by an unbanded pair.  Soon after the nest was finished we began to see chases around the nest when we visited.  Apparently someone (we couldn't see who!) was interloping and perhaps trying to take over the nest.  That happens.  Without color-banded birds in that area, I can't be certain what the outcome was.

Today I was watching that nest again.  First an unbanded male showed up with nothing in his beak.  This was suspicious because both male and female bushtits continue to carry nesting material into the nest after it is finished and through incubation.  Soon after, an unbanded female arrived and went right to the nest.  Also with nothing.  Instead of going into the nest as the "owner" would, she peered in and then hopped about the nest, cocking her head as if to inspect the real estate.  The entire time the unbanded male stayed in a branch above as if keeping a look-out.

They left quietly to the north after a few minutes, neither one ever entering the nest.  Immediately from the direction they took and nearby I heard the sound of chasing bushtits (loud spits!).  I couldn't see what was happening, but I could hear it.   Then suddenly, a pair shot past me heading south, followed by a lone male.  It must have been the presumed nest-owner chasing off the interlopers.

I can't wait to have these birds banded!  Then things will become much clearer as they always do.

So why the fuss from the owner (assuming that what was happening?).  Well, sometimes owners are booted from their nests.  And sometimes neighboring females secretly lay an egg in a nearby nest -- usually while her mate stands guard.

So there is good reason for neighbors to keep neighbors away!

The second instance was a banded male (RCRX), nowhere near his own nest, chasing an unbanded male near that male's nest.  This went on for quite awhile while a female entered the nest several times with feathers.  What RCRX was doing is anybody's guess.   But last year another male (RXRG) did take over a neighboring nest while his own nest was being incubated by the female alone (not the usual arrangement).  After taking the other nest over and ensuring there were eggs present and being incubated, RXRG returned to his first nest to help feed the kids, leaving the female at the second nest to raise her kids alone.

There's a quite a bit more to THAT story.  It's very complicated.  But I'll save it for another day.