Singing in the Rain (Mockingbird Style)

Rain falling outside my window. Photo by Aaron N.K. Haiman

I few days ago, my daughter and I were standing in our backyard when it rather suddenly started to rain!

The rain was not a tremendous downpour, so we decided to stay out and enjoy the weather. And it turned out we were not the only ones to make that choice.

I was somewhat surprised to see a Northern Mockingbird (Mimus polyglottos) fly out of cover and up to the top of one of the trees near our yard. The reason form y surprise is that, most of the time, birds tend to seek shelter during wet weather. Exposure to wet weather generally means wet feathers, and wet feathers are cold making it harder for a bird to stay warm. A wet and cold bird then has to use more energy to maintain its internal body temperature, which means it will run out of energy faster. This in turn means that the bird will need to go out and find more food which is time-consuming, uses energy as well, and may expose a bird to predators. So, staying dry and warm seems like a good, general survival strategy.

A Northern Mockingbird fanning its tail in a similar way to the bird I watching in the rain. Photo by Aaron N.K. Haiman

However, this Northern Mockingbird had other ideas. It decided to ignore the many trees that could have provided the dense shelter of leaves or needles, and instead specifically choose a high and exposed branch with no leaves or shelter of any kind. In the rain, it started fanning its tail out and spreading its wings to catch the drops for a rain bath. It was wonderful to watch this bird enjoy the rainfall. And, as if to illustrate how much the bird really was enjoying its shower, it started singing! A bird singing in the rain!

This drove home a point that has been driven home for me many times, but still sometimes surprises me, and the point is this. Many birds are so well adapted to their environments that they often don’t need to guard and horde their energy reserves so jealously. They have the energy reserves to spend on getting a bit extra cold if it means getting some feather maintenance done. This birds was confident enough that it would be able to get warm, and get food, that it did not have to worry about the rain. It was even willing to get a bit extra wet and cold by taking some extra time to sing in the shower.

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Watching a Douglas’s Squirrel Harvester

A Douglas’s Squirrel sitting on a branch. Photo: National Park Service

In his “Wilderness Essays,” John Muir said that the Douglas’s Squirrel “…is the most influential of the Sierra animals, quick mountain vigor and valor condensed, purely wild…”

And a couple of weeks ago, while my family and I camped in Kings Canyon National Park, I got to see how some of this influence is wielded.

In the early morning, I spent a bit of time wandering through the forest around the campground. As I was exploring, and watching Mountain Chickadees and Brown Creepers and Williamson’s Sapsuckers and White-headed Woodpeckers, I heard a thud of something hitting the ground close to me. I paused and then heard another thud. I looked up and high above my head I saw a Douglas’s Squirrel (Tamiasciurus douglasii) moving through the branches of a pine tree.

The forests of Kings Canyon National Park are filled with Douglas’s Squirrels! Photo: Aaron N.K. Haiman

The squirrel was moving from branch to branch checking the various cones. It would climb out to the tips of the branches where the cones grow and carefully and quickly assess each cone to come to a decision on whether or not it was ready to be harvested. If it was ripe enough, the squirrel nibbled away any pine needles blocking the base of the cone, and would then chew through the stem of the cone.

Once it had the cone off the branch, the cone would fall from the squirrel’s mouth and plummet to the ground. At first, I thought that the squirrel had accidently dropped the cone. However, after watching this process repeat a couple of times, I realized the squirrel was intentionally dropping the cones, and attentively watching where they fell. After observing the fall of a cone, the squirrel would scamper to the next cone.

I watched this process repeat again and again for over forty-five minutes. The squirrel was very strategic in how it went about its harvest. It was clearly working its way down the tree from highest branch to lowest. It would run out a branch to check the cones on it, harvest the cones that it wanted, then run back towards the trunk. Then it would jump to the next lowest branch and repeat the check-and-harvest process. In this way, it systematically checked every branch on the tree.

In the time I spent watching it, this squirrel must have harvested and dropped at least twenty cones. In that time, it also took a break for a few minutes to stretch out on a branch and rest, it took a few shorter breaks to groom its fur, and it spent a bit of time calling out into the forest. I figured that once the squirrel had enough food down on the ground, it would come down and feast, but it never did. I had to carry on with my day, so I left the Douglas’s Squirrel to it’s.

When I returned home, I read up a bit on this harvesting behavior, and it turns out that my assumption that the squirrel would eat the fallen cones was wrong. Douglas’s Squirrels do harvest large numbers of cones, but they are for winter storage! Once the squirrel I was watching was done harvesting cones, it was probably going to come down to ground level and begin hiding all those cones away in various locations so that the squirrel can come back and dig them out once the snow is covering the ground and other food sources are scare.

Forests filled with, and shaped by, Douglas’s Squirrels. Photo: Aaron N.K. Haiman

And this is where a big chunk of that influence comes in because the squirrels never make it back to eat every cone that they stash. These uneaten cones, and the seeds they contain, are where new trees sprout, so by hiding cones and then leaving them, these squirrels are shaping the forest of the future! That is some serious influence!

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V Formation Aerodynamics – A Birding Naturalist Video

Have you ever seen a v-shaped flock of geese fly overhead and wondered, why do they do that? In this video I share some information explaining this interesting behavior. I also talk about the other species that also fly in v-shaped flocks, and dispel an oft repeated myth.

If you enjoy the videos I am creating, two ways to stay informed would be to subscribe to the A Birding Naturalist channel and/or become a follower of this blog.

Eurasian Cranes (Grus grus) flying a v-formation (Photo courtesy of Wikipedia)

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Partitioning the Trees

A few years ago I wrote a post on niche partitioning among herons and egrets. That post was inspired by watching several species of herons and egrets foraging for food along Putah Creek near Davis, CA, and the resource they were partitioning into niches was food.

Recently, as part of my work at the Sacramento-San Joaquin Delta Conservancy, I encountered another example of niche partitioning by herons and egrets. This time, the resource these birds are partitioning into niches is nesting trees.

One of the grants that I manage at the Delta Conservancy is at the Cosumnes River Preserve and it includes and grove of large Valley Oak trees that many herons, egrets, and cormorants use as a rookery (a rookery is a colony of breeding animals, generally birds). One way that the various species have evolved to utilize the same trees, and yet avoid directly competing with each other, is for each species to utilize a different part of each tree to nest in.

Great Blue Herons typically nest on the very tops of the crowns of trees, Great Egrets typically nest only in the upper one-third of the canopy, Snowy Egrets typically nest in the middle one-third of the canopy, and Black-crowned Night-Herons prefer to nest in the lower one-third of the canopy (see the image below).

Niche partitioning of nesting locations within a tree by heron and egret species

I think this stratifying of nesting locations is amazing! Species have evolved to fill so many different niches, and so many niches can be divided into finer and finer gradations. I wonder if there is really any limit to how many species can evolve, and how complex an ecosystem can develop, in a give location.

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So You Think Being Transgender is Unnatural?

Homosexuality has been observed in just about every species it has been looked for. Transgender animals may not be widely known, but that may just be a matter of less interest in looking for them and/or writing about them.

There are certainly some animal examples that represent various forms of transgender animals in nature. One is the California Sheephead (Semicossyphus pulcher) which is a fish that is born female, and then can become male later in life. Another example is found in the Green Frog (Rana clamitans) that reverses sex in response to various external factors, and this has been observed in other amphibians as well. But both of these examples are in lineages of animals that are pretty distantly related to us humans.

Photo of two lions one is male sex (left), one is female sex (right), but both display male characteristics.

Well, research published a couple of years ago in the African Journal of Ecology is an example much closer to us. In a paper by Gilfillan et al. from the University of Sussex, five lionesses in Botswana have been observed to grow manes, regularly roar and scent mark, mount other females, and display other very male-like behaviors such as killing the cubs of rival prides which females lions just about never do but is very common for male lions.

This is a mammal we are talking about.

Lions that are female in their reproductive organs, but male in behavior and in some aspects of their outward appearance.

In the wild. In nature.

So, do you still think being transgender is unnatural?

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It’s A Bird-Eat-Bird World

My wife, daughter and I were in Berkeley, CA this weekend visiting my mom and some friends. One morning, while we were having breakfast and watching the visitor to the bird feeders hanging not far from the floor-to-ceiling windows, we witnessed a pretty dramatic event.

A female or juvenile Purple Finch.

As we eat our breakfast, a group of three or four Purple Finches were enjoying their’s. Suddenly, a California Scrub-Jay made an ambush attach on the feeder! It flew in through the branches of the Incense Cedar, and startled the finches into a bit of a panic. One of the Purple Finches (either a female of juvenile bird) made a very bad decision, and flew directly away from the incoming jay which meant it crashed into the big windows right in front of us. The jay flew past the feeder, not stopping at all, and landed on a table near the big windows. It seemed from watching the flight of the jay, that landing on the table had been its plan. The finch was on the deck, stunned by the impact with the window. The jay looked down, watched the finch for a moment to assess its condition, and then jumped down, grabbed the adult finch in its beak and flew away toward a large tree that we are pretty sure this bird and its mate have a nest in! That’s right, as if it was pretending to be one of the small hawks or falcons, the jay picked up the stunned Purple Finch and flew off with it!

California Scrub-Jay

This whole event only took a total of about one minute, but it got us all talking and thinking a fair bit about what we had just seen. First off, What a sight to see! All of us around our breakfast table were pretty surprised, impressed, and a few were taken aback at seeing a predator prey interaction at such close range. Secondly, I have never seen a California Scrub Jay prey on an adult songbird, before! I looked it up, and while there are reports of similar behaviors, they are not common. Thirdly, was driving a finch into the window the jay’s plan? The jay seemed like it was aware of the window, as its movements never put it in any danger of colliding itself. The finch was either unaware of the window, or was so frightened by the jay’s sudden attack that it forgot about it. So, did the jay basically hunt the Purple Finch using a window? Jays, members of the corvid family along with ravens, crows, magpies, and others, are highly intelligent and have been observed using tools in a range of settings. So, using a tool such as a known window location to incapacitate prey certainly seems possible.

Regardless of whether or not the window was used as a hunting tool, or if the jay just got lucky, this was a pretty impressive sight to see. And those baby jays had a very big breakfast of their own that morning!

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ABirdingNaturalist Post on NatureWriting!

A post from AbirdingNaturalist has been accepted to the website NatureWriting! With the acceptance of my piece titled “A Vomiting Vulture,” I am now a contributor. This is the first time one of my posts has been featured on another website, so I am pretty excited!

NatureWriting can be found here.

My post can be found here.

Check them out!

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A New Visitor

Allow me to introduce you to OR-25, the most recent wolf visitor to the great state of California. This very handsome 3-year-old fellow recently left his Imnaha Pack in eastern Oregon. He decided to walk south and, just last week, crossed into California where he has been hanging out in Modoc County. His arrival, along with OR-7 who visited for most of 2012 before settling just north of the California/Oregon border to have babies and the Shasta Pack that has established itself in Siskiyou County in 2015, may indicate that wolves are starting a trend of dispersal and range expansion into this state. If this expansion continues, we who live in California may be lucky enough to encounter these long-lost members of our state’s wilderness. I am certainly hoping for it!

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Chinook Salmon of the California Delta

As part of my current job with the California Department of Water Resources, I assist in collecting data for a study that is monitoring predators in the Clifton Court Forebay (CCF). The CCF is where water is collected and then pumped into the California Aqueduct for transport to southern California. One of the challenges to providing water to southern California is that there are several threatened or endangered species that live in the delta. Fish that get sucked into the pumps of the aqueduct do not survive, so keeping state and federally list species out of the system is important. The study I have been working on the past four months is examining threats to the listed species. One component of that study is to catch predatory fish such as Stripped Bass (Morone saxatilis), Largemouth Bass (Micropterus salmoides), and several species of Catfish (Ictalurus spp. or Ameiurus spp.). Once captured, these fish are tagged with little transmitters that send out signals that can be detected by underwater microphones, called hydrophones, that are setup throughout the area. By tracking when and where these predatory fish go, we hope to be able to figure out a way to reduce the number that come into CCF and eat the listed species.

Fall-run Chinook Salmon

One of the listed species we are concerned with are Chinook Salmon (Oncorhynchus tshawytscha), and I got an up close and personal look at one just a few days ago. As the team I was a part of was fishing in CCF, I got a hit on the lure I was using. It felt like a brick had been dropped on my line as the fish swam away from me and the boat. As I worked to real the fish in, everyone on the boat was getting curious to see what species I had hooked, just how big it was going to end up being. When I had finally pulled the fish to the surface, we were all really surprised to see that it was a Chinook! We are not supposed to catch salmon, and generally they do not attack the lures we use, additionally salmon at this time of year are not really eating but are instead focused on finding a mate and spawning. So this really was a surprise! When we got it on board to get the hook out of its mouth we quickly measured it (61 cm), weighted it (6.55 lbs), and got it back in the water so that it could go on its way.

Getting to see this fish, the largest fish I have ever caught, to hold it and then to watch it return to the water got me thinking a lot about Chinook Salmon. I am starting a new job on Monday which will focus on restoring many areas of the delta, and listed species will be a large part of those projects, so I figured that learning a bit more about salmon would be a good idea.

It turns out that there are four different runs of salmon that move through the California Delta. The different runs are defined according to when the different populations enter freshwater as they travel up from the Ocean and San Francisco Bay through the Delta and up the various rivers of California. The four runs are the Central Valley Fall-run, the Central Valley Late Fall-run, the Sacramento River Winter-run, and the Central Valley Spring-run. Each of these runs are considered to be evolutionarily significant units and so are monitored and managed for their specific needs.

Central Valley Fall-run Chinook, like the one I caught, are the most abundant of the four runs. They move through the area from July to December and spawn from early October through December. There is a fair bit of variability from stream to stream. Fall-run Chinook are an important economic factor due to the large numbers that are caught by both commercial and recreational fisheries in the ocean and by recreational anglers  once they reach freshwater. Even so, due to concerns about population size and the influence of hatchery-raised Chinook, this run is listed as a species of concern under the federal endangered species act.

Central Valley Late Fall-run Chinook migrate into the river systems from mid-October through December and spawn from January through mid-April. Again, due to concerns about population size and the influence of hatchery-raised Chinook, this run is listed as a species of concern under the federal endangered species act.

Sacramento River Winter-run Chinook pass through the Golden Gate from November through May and then move into the Sacramento River from December all the way through early August. They then swim up the mainstem of the Sacramento River to spawn from mid-April through August. These salmon used to go farther up the Sacramento River watershed and spawn in the McCloud River, the Pit River, and the Little Sacramento River. However, the construction of several dams have not blocked access to these historical spawning grounds. Despite these dams, the population of Sacramento River Winter-run Chinook was able to maintain a fairly healthy level until the 1970s when they began to decline. By the early 1990s only about 200 spawning salmon were observed. In 1989 this run was listed as endangered under the California Endangered Species Act and they were then listed as endangered under the federal Endangered Species Act in 1994.

Central Valley Spring-run Chinook begin moving up the Sacramento River from March through September. They generally the find areas of cold water to wait out the summer and then spawn from mid-August through October. This run used to be the largest in central California however, only small remnant populations are left in small creeks that make up some of the tributaries of the Sacramento River. Some Spring-run Chinook still occur in the mainstem of the Sacramento and Feather Rivers, but they sometimes hybridize with Fall-run Chinook. The reduced spawning areas, small population size, and hybridization threat lead the Central Valley Spring-run Chinook to be listed as threatened under both the federal and California Endangered Species Acts in 1999.

So, there you have them, the four Chinook Salmon runs of the California Delta. There are many other runs in other parts of the state, all with their own unique stories and histories. It will be interesting to see how I will be interacting with these runs in the habitat restoration work I will be doing. I will keep you informed!

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Early March

Early March is a wonderful time in the central valley of California. It is becoming warmer, although this year it never really got that cold. A few rain showers bring welcome and much needed moisture to a region entering its fourth year of drought. The calla lilies are blooming and the first jasmine blossoms give the air the faintest hint of their wonderful, soft fragrance, a fragrance that will become much stronger over the course of the month. A few days ago, I saw my first Swainson’s Hawk of the year. These birds are just returning to the area after flying from as far a way as Argentina, and will be setting up their territories soon. Another first of spring that occurred a few days ago was my first Valley Carpenter Bee. It was a beautiful black female flying from flower to flower. Soon there will be lots of these large friendly bees zooming around. As my two-year-old daughter and I play in our front yard, yesterday, we watch a pair of Bushtits searching through one of the oaks that line the edge of the lawn. A pair of Bushtits (the same birds?) have built their hanging pendulum of a nest and raised a clutch of babies in this same oak tree for the past two years. Will this be year number three? Laying on the lawn, we find the remains of last year’s nest which has only now fallen from where it hung. The long sock-like construction of moss and lichen and feathers all held together by spider silk is soft to the touch and impressively flexible and elastic! We also see American Crows starting work on their nest. The pair, and a few helpers, have chosen to nest near the top of one of the redwood tress in a neighbor’s yard. Some crows (again, maybe the same ones?) nested in this same tree two years. Last year they moved about 100 meters away and nested in a pine, but now they are back to their redwood tucking sticks together just a few feet from the top of the tree. While this breeding activity is ramping up, there are still many winter birds readying themselves for their vernal migration away from the central valley. Ruby-crowned Kinglets and Yellow-rumped Warblers call as they forage in the trees finding insects and building up energy reserves for the trip to the breeding grounds and the marathon that is a birds breeding season. Cedar Waxwings are also still around in fairly high numbers. Recently, there have been so many in the sycamore trees right outside our door that their high-pitched calling becomes a constant background noise behind any other activity. So much to watch and enjoy. I hope early March where you are is just as fascinating and enriching.

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