Time for an update on the bird family that is living in the light fixture on our front porch!
Last week (around June 14) I took a peek into the nest and the chicks were certainly bigger and were starting to sprout feathers:
Baby birds with feathers starting to grow!
I also saw something I find super interesting: The father bird came back to the nest! Admittedly I don’t know much about birds (but I’m learning!) and I assumed just the mother bird looked after the chicks. But the father came back and saw me and started chirping at me. Was he telling me off in his own way?
The father bird perched on our string of Christmas lights near the nest. (I guess it’s a good thing we were too lazy to take down the lights so that Mom & Dad bird have a place to stand guard…)
Watching both the Momma and Daddy bird go to and from the nest, I’ve been able to get a better look at them, and I’m pretty certain they are house finches. Super Interesting Observation #2: I’ve seen the Daddy bird feed the chicks! He’s a real hands-on dad.
Now, another week later, I looked through our front window at the nest and I saw baby bird faces! They’ve grown so big. So far I’ve been able to count four chicks. There were originally five eggs so I guess one of them unfortunately didn’t make it.
Three little opened beaks waiting for their next meal.
A close-up of one of the sweet chicky-faces.
A view of the nest from above. The chicks certainly look more like birds now.
It is amazing how much the chicks have grown in just two weeks. Mom and Dad keep going back and forth, feeding the little mouths.
Happy Father’s Day, Daddy Bird! What a sweet little family you have. Thank you for letting me watch and learn.
Mom and Dad house finch keeping watch on their chicks. Dad is on the left, Mom is on the right.
Like all living things, bumble bees eventually die. A queen bumble bee lives for about a year. She hatches around late summer, hibernates over the winter, and emerges in spring to start her own nest of bees. By the end of the summer, she dies. Worker bees and male bees live for only several weeks. It’s a short life but a very busy one.
A dead bumble bee. Rest in peace, sweet one. Photo source: Shutterstock.
This week for my #BeeFactFriday I tweeted that there are “undertaker bees” that remove dead bees from the nest. I’ve seen them do this. In the lab where I did my graduate studies, we had colonies of bumble bees which we placed in wooden boxes with a clear plastic top so we could see inside. These boxes were connected to a wooden, glass-topped tunnel that led to a screened flight cage–sort of like a gazebo where the bees could fly around. One day I saw a worker bumble bee carry a dead bee in her mandibles (mouthparts). She carried the dead bee through the nest, down the tunnel, and then dropped it inside the flight cage! An undertaker bee in action.
It makes sense that bumble bees would get rid of dead bees in their nest. Corpses take up precious space in a busy home, they could carry disease or parasites, and in my experience, dead bumble bees stink! Bumble bees like to keep a clean, healthy nest (for instance, they do all their pooping outside), and dead bees would be something they would want to get rid of.
After I tweeted my bee fact, I wondered: What, if anything, do we know about these undertaker bees? Has anyone done any research?
I came across a study that was published last year by a team of scientists from the United States and New Zealand. They focused on the species Bombus impatiens, the common eastern bumble bee, which is found across most of North America. I also worked with the common eastern bumble bee for my own research.
Bombus impatiens, the common eastern bumble bee, on a thistle. Photo source: iNaturalist.
The idea behind the scientists’ experiment was simple: place dead bees into bumble bee nests and see what the bees do. The scientists mounted a video camera above each nest box so they could record the behaviour of the bees.
The scientists had three colonies of bumble bees, all in their own nest boxes. To tell each bee apart, they labelled each worker bee by gluing a numbered plastic disc to their thorax (the middle part of their body). Where did they get the dead bees? They plucked some of the worker bees from the colonies and froze them. Poor bees! But it was the most humane way to sacrifice them while still keeping them intact.
Coloured, numbered discs were glued to the thorax of the dead bees, too, although a different colour was used from the live bees. Then, every so often the scientists placed five dead bees into each of the three nests. If a bee pulled on a dead bee with her mandibles, she was considered an “undertaker” and her “tug time” (the amount of time she spent tugging on the corpse) was recorded. A corpse was considered to be removed from the nest when it was tugged past the threshold of the nest entrance.
A worker bumble bee with the yellow label 22 drags the corpse with the blue label 8 through the nest. Photo source: Insectes Sociaux journal.
When there were no corpses in the nest, the scientists watched and classified other behaviours. “Nursing” was when bees fed larvae (baby bees), kept the baby bees warm, made honeypots out of wax, and inspected the larvae and honey pots. “Guarding” was when bees perched near the entrance of the nest, fanned their wings (to keep the nest temperature steady), or patrolled the nest. “Foraging” involved going outside the nest to collect food (pollen and/or nectar). Bees who sat still in the nest and seemed to do nothing were labelled, “inactive.”
So, what did the scientists find? About a third of the bees in a nest participated in corpse-tugging at some point. “Guard bees” tended to spend more time tugging corpses compared to the other tasks of nursing, foraging, or being inactive. These more consistent corpse-tugging “undertaker” bees tended to be bigger than other bees, and the bigger bees tended to be more successful in fully removing dead bees from the nest. Interestingly, on more than one occasion, one bee was seen dragging a corpse to the back of the nest, away from the entrance, digging a hole, and placing the dead bee inside the hole. Why did she do this, instead of taking the dead body outside the nest? The scientists don’t say in their report whether these corpses were left buried or whether they were eventually dumped outside the nest. Still, pretty peculiar that only one bee did this.
The team of scientists point out that it makes sense that guard bees would act as undertaker bees. Guards might be more likely to notice changes inside the nest, such as the presence of a dead body. Dead bee bodies probably give off chemical cues, such as a distinctive smell, that the bees can detect. So maybe there aren’t really “undertaker bees” after all, but instead, corpse disposal is just one task of guard bees.
Reference
Walton, A., Jandt, J. M., & Dornhaus, A. (2019). Guard bees are more likely to act as undertakers: Variation in corpse removal in the bumble bee Bombus impatiens. Insectes Sociaux, 66, 533-541. https://doi.org/10.1007/s00040-019-00718-8
About two weeks ago I told you about birds that built a nest in our front porch light. And I couldn’t get a good photo of the momma in the nest because she kept showing off her butt. Well, here is an update! And it is exciting.
Several times a day I look out our front window at the light to see how things are going in the nest. Momma still shows me her butt now and then, but now I often see her hunkered down and her sweet little eye seems to be watching me. I try not to scare her, so I just peek from the side of our window. This week I realized it’s been a while since I took the photo of her two eggs, so I waited until Momma was not in the nest and I took another picture. Look at this:
Look! Now there’s FIVE eggs!
There’s no longer two eggs, but FIVE eggs! Wow! Momma has been busy. This is so exciting!
But wait, it gets even better.
This morning I thought I’d check in on them. And look! Babies!
Brand new baby birds. Hooray!
They are so new and pink and beautiful. And as you can see, there is one egg left, or maybe it’s just an empty eggshell. It’s hard to count the babies because they are in such a tight little bundle. I hope, if it is a full egg, that the baby is just a late bloomer. But it got me thinking: What happened to all the other eggshells? From what I could find online from reputable sources, adult birds can eat the eggshells (a good source of calcium), or they fly from the nest, carrying the eggshell, and drop it far away. It’s not good to keep eggshells in the nest because: (1) they take up space in an already squishy home; (2) they are sharp and can cut the delicate baby birds; and (3) the exposed inside of the egg is not camouflaged like the outside, and can act like a beacon to predators. Which made me think, Aha! No wonder I sometimes find empty half-eggshells lying around outside, seemingly nowhere near a nest. Momma bird dropped it far away as part of her parenting duties.
Welcome to the world, little ones! You are such sweet little pink packets of joy, and I look forward to watching you grow.
I recently discovered even more evidence that bumble bees are awesome.
A team of scientists in Switzerland and France saw bumble bees biting holes in the leaves of some black mustard, eggplant, and silverleaf nightshade plants. No one had ever reported bumble bees biting leaves before. From what the scientists could see, the bees were not eating the leaves. They were also not bringing pieces of leaves back to their nest. So why the heck were they biting them?
The scientists knew that when some plants experience stress they tend to grow flowers. The plants that the bumble bees were biting did not have any flowers yet. Were the bees trying to speed up the plants’ flowering process?
Also, the scientists suspected that the bumble bees were after pollen. The bees were starting new colonies, and larvae (baby bees) need pollen as a protein source to grow. The bees might have been saying to the flowers, “Hurry up and flower! We need some pollen!”
This was a perfect circumstance for an experiment! And they way the scientists investigated this leaf-biting behaviour was very clever. They used laboratory and field experiments.
First, the laboratory experiments. The scientists let buff-tailed bumble bees (Bombus terrestris, widely found in Europe) fly around tomato and black mustard plants that only had leaves but no flowers. After the bumble bees had bitten 5 to 10 holes in the plants’ leaves, the scientists removed the plants. Then they did something really smart: They paired each bee-damaged plant with a plant that they had damaged themselves using forceps and a razor, to copy as closely as possible the way the bees had bitten the leaves. The result? The bee-damaged plants sprouted flowers up to 30 days earlier than normal, undamaged plants or plants that were damaged by the scientists. By biting the leaves, the bumble bees were speeding up the plants’ flowering process! Amazing!
A: A bumble bee using its proboscis (tongue) to pierce a hole in an eggplant leaf. B: A bumble bee biting a leaf with its mandibles (mouthparts). C: What bee bite-holes look like in the leaves. Source: Science journal.
For the next laboratory experiment, they gave some colonies of bumble bees lots of pollen in their nest, whereas for other colonies they gave none: the bees had to go out and get it themselves. The scientists then let bees from both types of colonies (pollen-rich or pollen-deprived) fly around young black mustard plants that had no flowers yet. They found that bees from pollen-deprived colonies bit holes in the plants’ leaves way more often than the bees from pollen-rich colonies. This is a convincing sign that the bees were biting the leaves in order to “tell” the plants that they needed pollen.
And finally, the field experiment. The scientists wanted to make sure that this leaf-biting behaviour happens in natural environments and not just in laboratories. So, they put some young colonies of bumble bees on the rooftop of a university building, along with some plants that had not flowered yet. They did this from March to May. This timing was important. Their bees were free to fly wherever they wanted to get food, but in March there wouldn’t be any flowers anywhere yet. But come May, there would be plenty of flowers to be found beyond the rooftop garden. Sure enough, the scientists discovered that the bees damaged many more plants in the early part of spring when no flowers could be found, but that damage decreased as spring progressed and flowers started to appear elsewhere.
The field experiment was also run between June and July, when plants are in full bloom. The scientists offered their rooftop colonies of bees some plants that had not yet flowered. The result? There was way less leaf damage to the flowerless plants they had placed near the colonies, presumably because the bees were flying farther to get pollen elsewhere. But the really cool part? They saw different species wild bumble bees biting holes in the leaves, too–not just bees from their own colonies! Wild bees, then, bite leaves as well.
What I think is so cool about all of this is that bumble bees have somehow figured out a way to make plants bloom faster when they are just establishing their families and are in need of pollen. This could be an adaptation to cope with climate change: cooler springs make it less likely that flowers will bloom on time, so bees help them speed up. And what’s even extra cool is that it is not just leaf damage alone that causes the flowers to come out early: something about bee bites in particular makes the plants sprout flowers. Are they injecting some kind of chemical into the plant? Do bumble bees have magic spit?
Sigh…bumble bees are amazing.
References
Pashalidou, F. G., Lambert, H., Peybernes, T., Mescher, M. C., & De Moraes, C. M. (2020). Bumble bees damage plant leaves and accelerate flower production when pollen is scarce. Science, 368, 881-884. DOI: 10.1126/science.aay0496
Chittka, L. (2020). The secret lives of bees as horticulturists? Pollen-starved bumble bees may manipulate plants to fast-forward flowering. Science, 368, 824-825. DOI: 10.1126/science.abc2451
The other morning I was sitting at our dining room table (my writing spot) when I noticed some commotion outside our front window. Two small birds were flitting around one of the light fixtures above our front porch. My heart swooped. Are they thinking of building a nest? In the past birds had used our light fixtures as a home but it’s been a long time since that happened.
(Which makes me wonder, why did they stop building nests there? How does a bird decide where to build its nest? Does it depend on the type of bird? Questions for another day and another blog.)
A little while later, when the birds were not around, I went outside to look. They WERE building a nest! Hooray!
Our lucky light fixture that might be a new home for birds!
A bird’s-eye-view (ha-ha) of the beginnings of a nest.
It is amazing how fast those birds work. I didn’t time them, but it was like less than an hour or something from when there was nothing in the light fixture to the scaffolding of a nest seen in the photos above.
Then I felt a twinge of panic. What if we turned on the porch lights at night? With two small children in our house I couldn’t guarantee that everyone would remember to leave the lights off. The light would blast the birds and they’d be terrified, I’m sure. And then they might abandon the nest and they’d have to find someplace else and start all over again. And selfishly, I want the birds to stay so I can watch them start a little family!
I have to unscrew the lightbulb, I thought. So I waited until the birds were gone, stepped up onto a stool, and tried to unscrew the bulb. But it was tricky. Because of the metal ornate design it was hard to get my fingers around the bulb. Then I got it, and unscrewed it…but then it fell onto the nest! AAAaaaahhh!!! Isn’t there a saying somewhere that if you touch a bird’s nest the bird won’t come back?? Nooooo!!! I panicked. I frantically reached in amongst the (annoying) metal loops and swoops of the fixture and eased the lightbulb up so it rested on top of the socket. Phew. I hope the bulb didn’t contaminate the nest…
(Note: Here is what Scientific American and the Alaska Department of Fish and Game have to say about disturbing birds’ nests. According to them, birds might abandon a not-quite-finished nest if it is disturbed. But birds will not abandon their babies.)
I hurried back inside, crossed my fingers, and waited eagerly for the birds to come back. And they did! Phew. They worked on their nest and by the end of the day, it looked like this:
The birds came back and continued to build their nest! But it’s not quite finished yet, as the bottom still has some spaces.
By the end of the next day, the nest looked completely finished:
The nest is finished! Hooray!
Next, I wanted to figure out what kind of birds we are hosting. I saw them flying around the nest and they were always moving, so it was hard to get a a good, close-up look. (I watched them from inside our house at our front window.) And each time a bird was in the nest, all I could see was her butt! She always faced her butt to our front window:
Anytime the momma bird was in the nest, all I could see was her butt…
From what I could see when the birds had been flying around building their nest, there was a male and a female. The male had soft, blushy red around his head and neck, and the female was a speckled brown. After looking at photos online I think we have a family of house finches (Haemorhous mexicanus).
A male house finch (left) and female house finch (right). I think this is the type of bird that built the nest. Source: iNaturalist.
For the past couple of days whenever I look out our front window, I can see the momma bird hunkered down in the nest. I can just see the top of her head. If she’s staying in the nest a lot, that could mean she is laying, or has laid, eggs!
Yesterday I waited until momma left the nest for a bit (probably to grab a bite to eat?). I peeked into the nest and…look what I found!
Look at the two beautiful eggs in the nest!
Yes, I am a huge animal nerd. But there is something so sweet and heartwarming to know that you’re sharing your home with little wild sparks of life.
Admittedly I don’t know much about turtles. So when I found out today is World Turtle Day, it was the perfect opportunity for me to dig around for some interesting research on these aquatic creatures.
A few years ago, two scientists from the University of Tennessee, Knoxville did a clever experiment and discovered that one type of turtle, the Florida Red-bellied Cooter (Pseudemys nelsoni), can learn from each other.
A Florida Red-bellied Cooter. Source: iNaturalist.
A person holding a Florida Red-bellied Cooter to show its size. Source: iNaturalist.
The scientists came up with the idea because not a whole lot is known about whether turtles are social or not–you can sometimes see them basking in the sun together and they get together to mate, but do they actually “hang out” together? The scientists saw some behaviour in a group of turtles that looked like they were behaving socially. They also witnessed turtles copying one turtle who tried to get a yummy leaf that was hanging over the surface of the water. Maybe turtles are more social than we think? The second observation in particular led to the question: Can turtles learn from each other?
In their laboratory, the scientists had six Florida Red-bellied Cooters. These turtles had hatched in their lab and lived in captivity in a big tank of water. The scientists set up a tank where at one end there were two bottles sitting above the water surface on bricks. One bottle was white and the other was black. Under one of the bottles was a food pellet. The scientists trained two of the six turtles how to knock one of the bottles over to get the food pellet: for one turtle, the pellet was always under the white bottle, and for the other turtle, the pellet was always under the black bottle. Interestingly, one turtle always knocked the correct bottle over by swiping at it with its front legs, whereas the other turtle knocked the bottle over by biting at it. (The scientists swapped the positions of the bottles every so often so that the turtles had to learn the colour of the correct bottle, rather than its position.)
The set-up the scientists used in their experiment. On the left you can see the top of the white bottle and the top of the black bottle. Underneath one of the bottles is a food pellet, and the turtle had to learn which colour bottle to knock over to get it. Here a turtle is climbing up toward the black bottle. It has paint on its shell so the scientists could tell the turtles apart. Source: Journal of Comparative Psychology.
Soon the two turtles learned to knock over the correct bottle to get the food. These turtles were called the Demonstrators. The scientists then put the remaining four turtles, one at a time, with one of the Demonstrators, so they could watch as the Demonstrator knocked over a bottle to get the food pellet. These four turtles were referred to as the Observers. Then the scientists placed each Observer alone with the bottles to see what they would do. Did they learn how to get a food pellet simply by watching a Demonstrator?
When tested on their own, all four Observer turtles chose the correct bottle: if their Demonstrator had to knock over the black bottle, the Observer chose the black bottle; if their Demonstrator had to knock over the white bottle, the Observer chose white. But the funny thing is that the Observers simply approached the correct colour of bottle or just touched it with its snout. They did not attempt to knock over the bottle, like their Demonstrator had done. I wonder why? The scientists aren’t sure either. Maybe the Demonstrator turtles’ big shell blocked the view of the Observers so they couldn’t see exactly what the Demonstrator did to knock over the bottle? More research could perhaps provide an answer.
The cool thing is that turtles learned from other turtles which bottle to choose. And I think it’s neat that the Demonstrators had their own way of knocking over the bottles. This research scratches the surface of what is going on in those reptilian brains. What else is waiting to be discovered? Maybe turtles have more of a “social life” than we think.
Two Florida Red-bellied Cooters. I wonder if they are communicating with each other somehow? Source: iNaturalist.
Reference
Davis, K. M., & Burghardt, G. M. (2011). Turtles (Pseudemys nelsoni) learn about visual cues indicating food from experienced turtles. Journal of Comparative Psychology, 125(4), 404-410. DOI: 10.1037/a0024784
By Dana Church
