The American Robin: An Exciting Tale of (almost) Null Results

Photo by: Stephanie B.

Ask anyone living in the United States to point to a robin and they can do it with ease. The robin, more precisely known as the American Robin, or Turdus migratorius, is the most recognized bird by the average person. They are larger than most other songbirds and have a distinctly red breast that colors most of their front side. Robins have a deeper-sounding song than other birds, and is fairly easy to detect amongst the smaller birds. Take a listen with the sound clip below, and test your skills.

Robin Bird Call (Audubon Society)

As a group, prior to zeroing in on the robin as our species of choice we decided we wanted to do a study experimenting with foraging ecology, a subset of behavioral ecology. As a concept it looks to study energy spent foraging for food versus energy obtained from the foods, and analyzing what factors may be affecting this trade-off. We toyed around with experimenting with ants at first, but found difficulties finding enough suitable populations of them. Next, we moved onto the robin. We knew they lived on and near campus, and knew we could easily spot them. They became a reliable species to study considering our time and distance restraints. Plus, they’re neat to watch pulling up worms.

Next, we looked into what might affect a robin’s foraging time. Human disturbance was a quick choice because almost all animals seem to now be affected by some sort of anthropogenic disturbance. Next we determined how best to quantify disturbance; we chose to do this by counting number of people passing by the robins we were observing. Overall, our question became:

How does the presence of humans affect the foraging time of the American Robin?

Photo from: http://vireo.acnatsci.org/bird_academy/what_birds_eat/worm-eating %20birds.php

We thought American robins would spend less time foraging when affected by more disturbance. Disturbance was categorized as any nearby human presence including walkers, bicyclists, and passing cars.

Our study was an observational point-count study. Through selective randomization we chose ~30 sites to observe robins. The sites were a mixture of high and low traffic campus locations, tree lined areas of campus, and forested areas in the Sehome Arboretum. An observer was sent to a site and stayed observing for 30 minutes. During this time they recorded the foraging time of any robin they saw land. The start point for time spent foraging was dictated by the instant that a robin landed and exhibited foraging behaviors and end point was when the robin flew away to refuge or stopped exhibiting foraging behaviors. While robin foraging time was collected surveyors tallied human passing by at the respective distance categories. Other data recorded included observer, date, site location, percent cloud cover, wind, precipitation, and general disturbance notes when no birds were observed.

Map of study sites

After collecting our data we did a regression analysis to compare people passing by within 10 meters or less versus time spent foraging and another one of total people within sight versus foraging time. We found no significant correlation between the time a robin spent foraging and the amount of people passing within 10 meters. However, we did get significant results when we compared total number of people versus time spent foraging. This indicated there was a significant relationship between the two, however, it may be due to other factors that we did not consider, since we also had a very low R2 value.

Figure 2. Effects of human presence on foraging time 
(n=45). Graph presents regression results between
total number of people passing by vs time robins 
spent foraging on Western Washington University’s 
campus and the Sehome Hill Arboretum. 
P-value: 0.0044. Adjusted R2: 0.1548.

 

Figure 1. Effects of human presence on foraging time 
(n=45). Graph presents regression results between 
number of people passing by less than 10 meters
away versus time robins spent foraging on 
Western Washington University’s campus and the 
Sehome Hill Arboretum. 

P-value: 0.6707. Adjusted R2: -0.0189.

To consider what else might have led to these results we compared the three habitat types. We conducted three one-way ANOVAs comparing the habitat types (categorized as forested, open field, and boundary areas) versus foraging time. These tests also provided no significant results.

Overall, we do not feel confident our data produced any strong results. However, it’s important to consider some shortcomings which may have affected our results. First, we did not exclude outliers from our data. Though this may have provided a stronger correlation, it also would have caused us to lose data. We also were only able to collect data from 17 of our 30 selected sites. If we had more time, we could have collected more data. Lastly, we should have taken food abundance into account as robins may have been able to locate food better in manicured lawns than underbrush.

While we are left with unuseful results, we do not mean to alleviate any concern people may have on their effect on robins. We recommend landowners consider habitat and prey implications for the American robin before building or changing landscapes. Although we found no direct effect of human disturbance on robin foraging times, it’s possible habitat changes could have an indirect effect via prey or predator changes.

The Pursuit of Knowledge and Crows: Patrick Verschoor, Marissa McBride, Maia Gurol, Cat Lasswell

As scientists, we work hard to study questions that interest us, and to gain an understanding of the natural world. It is a deep fascination with the world that leads us all to pursue scientific knowledge. What our group wanted to gain knowledge of was the American Crow, and in our pursuit of that knowledge, we have learned much.

Joe McKenna/Flickr Creative Commons

Crows are some of the most common birds found in areas largely affected by anthropogenic influence. They are opportunistic feeders, which is one of the main reasons they have been so successful in urban and suburban settings where disposed food and other small animals are plentiful and available. Suburban settings are comprised of varying levels of human development including neighborhoods, small businesses, and parks, each of which provide foragers with different food options. Crows are extremely intelligent and can recognize regular sources of food and return to those areas for future feeding options. Though crow abundance increases in developed areas, studies have also shown decreased size and overall health of crows that feed primarily on processed food. For this study, we wished to better understand how crows exposed to a variety of food sources choose from the plethora of available options, and if these selections have anything to do with the location of foraging.

Image credit: Urban crows eating garbage / Crafty Green Poet

We performed our experiment in Bellingham, a medium-sized city along the northwest coast of Washington state. We chose three distinct suburban locations, including alleyways near the local university, forested parks, and parks located along the coast of Bellingham Bay, and offered them food options commonly found each location, including processed turkey meat, a feeder mouse, and a mussel, respectively.

This quarter we have learned through hands-on experience that data collection can be at times difficult, uncomfortable, and unproductive. Finding the time in four people’s busy schedules can be essentially impossible. You also have to schedule around the time when your target animal is going to be detectable, making it even more difficult to collect a large enough set of data. Luckily, crows are not very difficult to find. They are deep black and medium sized, making them stand out in most locations. They are also very loud, and do not seem afraid of humans. Finding crows was not very challenging, gathering data for our experiment was much harder. In fact, half of all of our observational periods were unsuccessful in yielding any data. We did a total of 18 trials in our six locations, and only collected results for nine of them. Considering that each trial look us 20 minutes, that’s a total of 4.5 hours of unsuccessfully trying to get crows to go for our bait. We found that playing Crow calls, as in this video helped attract more Crows:

Though we had some difficulties, learning about crows this quarter was absolutely fascinating and entertaining! Crows that did not go for our bait were replaced by seagulls, park cleaners, and small children. There was one instance where Patrick had to frantically yell at a group of toddlers huddled around our dead mouse. One of the toddlers had almost picked the mouse up and was barely stopped. The presence of dogs were also a constant and worrying threat to both our experiment and the dog’s health. Luckily, none of our bait was eaten by dogs. We also observed some sort of hierarchy among certain birds. While Marissa and Maia were in the alley behind High St., two crows approached the selections of bait. There was a small fight or tussle, and the one of the crows flew down to make its selection first. It sniffed the turkey meat, and then moved on to the mouse, picked it up and flew away. Then the second crow was then able to approach the remaining food options. This crow also sniffed the turkey meat, moved on, and selected the mussel.

Image credit: Dave W / flickr

      

Throughout these last ten weeks, we have overcome small children, the smell of decaying mussels, and bloody mice, but thankfully, we did learn something. We found a slight preference towards the feeder mouse in all three locations, but statistical tests did not reveal a significant correlation between food selection and location. This goes completely against our hypothesis but does hint at some sort of correlation. As most proper scientific experiments do, this raised more questions for the team. Why was the mouse picked? Simply because it is more visible? More nutritious? Preferred in Bellingham? Do crows and seagulls prefer different foods? Though inconclusive, continuing research on feeding preferences of animals that thrive in anthropogenically altered spaces could be highly informative to future crow management, as well as the greater concept of human coexistence with the natural world.

This is a Youtube video made by BBC demonstrating some of the amazing things about crows. Their ability to recognize faces and use tools is so mind-boggling! Crows make you question whether calling someone a “birdbrain” is really an insult:

Laurel Park at Dawn

I feel that every class I have taken so far at Huxley has imparted upon me a greater sense of awareness of the natural world my everyday surroundings. This class in particular has exposed me to many of the animals that I took for granted and failed to appreciate on a daily basis. Learning to slow down and really notice the behaviors and patterns of the organisms that comprise their local ecosystem is an experience I hope everyone chooses of which to be a part.

As you slow down you start to notice the unique and dynamic beautify that one often passes by. I myself try to identify as many plants and animals as I can on the various routes I take traveling in between campus and my house. For this project I wished to observe animals in Laurel Park, an area through which I pass almost daily. I also wanted to observe at a time that I am not usually there. I am rarely awake at sunrise, a habit I am sure is shared by most of the people who live around the university, so this seemed the perfect time to make observations.








Closer examination of this Douglas fir tree reveals what I believe is the larvae of a tree-boring beetle. This tree looks to be in healthy condition, but these beetles usually inhabit only dead or dying trees. This could be a sign that this tree is on its last years.








It is Thursday May 28th. In a vacant Laurel Park, I hear birds singing as I approach the park, seemingly undisturbed by my presence. It is 5:38 in the morning and the temperature is chilly, but surprisingly warm for this time of day, around 57 degrees Fahrenheit. The sky is already bright blue, and it feels like the middle of summer. There is a very slight breeze coming from the northwest and the air smells fresh and clean like a new day. The empty park feels energetic and complete even without the presence of the intended human visitors.

There are many animals presence, detectable both visually and audibly. I am familiar with the crow calls that are the most obvious in this video. They sound like they are making the "rally" call, which is a series of short "caws" and is intended to attract other crows to the area. I am not 100% certain about the other birds that you can hear on the video, though I believe I heard a robin. This is supported by the fact that I saw a bunch of robins when I first arrived at the park, though I was unable to take a good photo because my phone died after taking this video.

Mornings are some of the most common feeding times for many organisms. In hotter seasons/climates, organisms do this to avoid the extreme heat in the middle of the day. Here in the mostly cool climate of the Pacific Northwest, this habit also appears to have a lot to do with food availability being more active and visible during early morning and evening. It could also have to do with human presence being at its lowest point in most locations during the night and early morning.

There are also obvious signs of human presence in the form of litter. This park is located in the dead center of the "North campus" neighborhood that is inhabited mainly by university students. Though the park is generally clean and one feels safe walking around barefoot, cans of alcohol and candy cans be found around the perimeter of the park. This is a can of Steel Reserve malt liquor I found on the North side of the field. 




In this moment, sitting alone in the middle of a field at 6:32 in the morning, I feel special for having been the sole witness to the awakening of Laurel Park today. My brain feels like it is a zen state of meditation. I fell calm, well-rested, and connected to the fellow members of my natural environment. I am, and hope to continue to be in the future, a person that is mindful and aware of how my actions play an influential role in the shaping of this unique and dynamic ecosystem on which we depend. This is a wonderful and empowering feeling. I believe deliberately exposing oneself to the nature is necessary if we wish to cultivate our development of a more aware and educated population. This video is merely some cob webs and bug parts stuck to a Douglas fir tree, but by slowing down and studying it you can almost see it dance in the slight breeze.

As my hour of observation comes to a close, I begin to spot people waking up and starting their day. The sky is starting to loose the soft and sleepy glow that is restricted to the indecently early hours of the morning. The birds are still chirping loudly.

Preferences of Pollinators

Bee pollinating an invasive Himalayan blackberry, Photo by: Chris Trinies

Pollinators help propagate flowers by moving from flower to flower searching for nectar as an energy source, and taking pollen along with them.  The most well-known pollinators are bees but “pollinator” refers to any species which habitually moves from flower to flower. Bees, beetles, bats, flies, moths, butterflies, and hummingbirds are all examples of pollinators in the Pacific Northwest. Because most plants cannot reproduce without the services of pollinators, it is crucial to both natural ecosystems and agricultural crops that pollinators are abundant and active. 

Little beetle peeking out of a native Thimbleberry, Photo by: Chris Trinies

When foreign plant species are introduced to a non-native region, they may not have the same restrictions on growth as they do in their native habitat (i.e. no herbivores here will eat them) and can outcompete the native plant species which do feed local herbivores, and greatly reduce the amount of herbivore forage in the region. They can outcompete in many different ways, some have poisonous berries, and some grow so rapidly they crowd out competition, and is possible that some may reproduce at a greater rate.  However, the easiest way for a plant to reproduce more is to attract more pollinators.

Budding invasive Himalayan blackberry, Photo by: Chris Trinies

This raised the question: Do the pollinators in the Sehome Hill Arboretum have a preference between native and introduced plant species?

We ran a study to find out!  

We instructed members of the class observe different plants (some native, some introduced) and record how often the plant was visited by pollinators, then compared native and introduced plants.  We didn’t get any statistically significant results, which means that we can’t say from our observations alone that is definitely a difference in pollinator visits per minute between native and introduced species of plants.  This is either because our study wasn’t large enough or because pollinators in the arboretum just don’t have a preference. Considering how many other studies found that pollinators have preferences in plants, it’s more likely that our study just wasn’t large enough.

We certainly learned more about pollinators and about what plants are native to the area by doing this study than if we'd tried to do a manipulative study in a controlled setting. One example was that the beetles we found on the thimbleberry flowers completely caught us by surprise and changed how we did the observations. Looking up all the plant species in the field was something we’d never really done before either. All in all this study was a great learning experience for future field work.

Monarch butterfly, Photo by: Larry Keller, Flickr

Before this study I don't think any of us really would take the time to sit and watch pollinators buzz around. Once we had it was actually pretty incredible. Different types of pollinators do exhibit different behaviors! Whether that be in the different ways that they get around, the way that they interact with other pollinators, how they act when they land on flowers...there are just so many differences among pollinators that are truly something to marvel at. I would consider this as a kind of "stop to smell the flowers" kind of experience. When you take the time to observe something so seemingly small, it becomes more apparent just how abundant and important little critters like pollinators are. 

To drive the point home, lets give the pollinators a little round of applause for contributing so many wonderful foods in our lives!

Almonds, Photo: Rune T, Flickr

Avocados, Photo: Samantha Thayer, Flickr

Chocolate, Photo: Bakerella, Flickr

So many fruits!, Photo: John, Flickr

Coffee, Photo: Zach Inglis, Flickr

Berries, Photo: Gunna, Flickr

Beautiful Vegetables, Photo: Enri Endrian, Flickr

*For a more comprehensive list of foods that pollinators contribute, visit:

http://naturalsociety.com/list-of-foods-we-will-lose-if-we-dont-save-the-bees/

By: Erika Bash, Chris Trinies, Dustin Gleaves

Mid-Day Coffee with Malacosoma californicum

The common western tent caterpillar (Malacosoma californicum) is considered a pest to many, and an arch nemesis to the fruit farmers of the northwest.  I will admit, when I see a gaggle of these buggers in my garden I typically cut them down and toss them into the waste pile. But on their own they are pretty cute. I consider them to be the fluffy kittens of the invertebrate world.

I would like you all to meet Gerry. I named my new found friend Gerry because he seems like a regular guy, nothing appeared out of the ordinary about this caterpillar at first sight. As the tent caterpillars come out in the month of May I usually refer to them as "those damn things again," but on his own Gerry seemed harmless, even invisible.

Where is Gerry?

 Ah, there you are.

Some may say caterpillars are insignificant, and extremists have recommended we start a NASA program to blast all of them into the sun. But Gerry knows to ignore the haters. He may look squishy and weak, but more informed individuals know that Gerry spent the entire winter out in the elements while he was still an egg. 

Living on the edge

Gerry summits trees and buildings equivalent to a human scaling the Empire State Building, without the aid of silly ropes and harnesses. He defies gravity because he knows that in 5 to 6 weeks he will go on a small vacation and when he gets home he will rid himself of his legs and take flight. Gerry looks forward to this day so much it seems as though he is ready to fly off right now.

Whoa Gerry calm down there! No need to rush along your life cycle, these things take time. Did you hear me Gerry? ... Gerry?

Why have you done this cruel caterpillar gods?

Oh wait a minute, what is this? Gerry survived the fall! He survived a human equivalent of a 60 foot drop right on to his back and he isn't phased in the slightest. Not bad for a creature who doesn't even have a spine. 

Again Gerry? Really?

He may not be the smartest caterpillar in the tent, but judging by his willingness to risk his life in search of some plants to munch on, I would say he is the toughest.

A Flock of Tree Swallows named "Luke Skywalker"

After my plan to begrudgingly set our small mammal traps at Lake Terrell Wildlife Area with the rest of the class was foiled by my arch-nemesis “Hay Fever”, I found myself conveniently sitting below what I could only describe as a “Bird Condo”. It was made up of four bird houses each with four sills to perch on with a conjoined cavity inside. Whoever was leasing the condo was doing something right because there was a plethora of bird species utilizing it.  One group of tree swallows, Tachycineta bicolor, caught my eye immediately by their incredibly dexterous aerial maneuverability.

The "Bird Condo" at Lake Terrell Wildlife Area. (Picture taken by Robinson Low on phone)

                This particular group was comprised of 3-5 males and 2-4 females. It is currently the tree swallow’s breeding season so you can imagine the competition and constant bickering between the males of this group. Add this to their acrobatic twists and turns and I couldn’t help by imagine myself in the middle of the finalspace battle between the Imperial and Rebel forces in Star Wars Episode VI Return of the Jedi. 

                My focus kept returning to their aerial fluidity. As they climb in altitude their frantically fluttering wings seem awkward and energy inefficient.  But once they reach cruising altitude or are descending their wings don’t seem to move at all. Rather than flapping their wings these swallows make use of incredibly precise shifts of the angle of their wings to maneuver through the air. Their knowledge of how wind patterns and aerodynamics affect their flight rivals that of all three Wright Brothers combined.  Specifically, as a tree swallow would approach the bird condo instead of quickly flapping its wings to slow down they angle their wings up, increasing wind resistance. Extraordinarily energy efficient. These precise changes to their wing angle remind me a lot of how pectoral fins on a shark work.  They transition from the awkward, “TIE-Fighter”-esque, wing flapping to the efficient, “X-Wing”-esque, soaring in the blink of an eye.

Two Tree Swallows dive, duck, dip, dive and dodge around the bird condo.(Picture taken by Robinson Low on phone)

Three Swallows continue frolicking. (Picture taken by Robinson Low on phone)

                As is typical of birds they don’t stay in the same spot for very long. This happened with my group of tree swallows and seeing as I cannot fly to continue following them I decided to observe the activity of the bird condo while they were off adventuring.  A lone Purple Martin, Progne subis, perched atop the roof of the bird condo as if observing something far off in the distance. As if on queue out of the corner of my eye I saw large movements coming from the trees lining the water some 500 meters down the lakes edge. A few Great Blue Herons, Ardea herodias, had ventured too close to a Bald Eagle, Haliaeetus leucocephalus, and the Eagle had begun chasing them away, squawking to assert its dominance over the area.  It seemed as though the purple martin had been watching them from afar, like Emperor Palpatine watching countless Star Destroyers and Star Cruiserswage war in that final battle. 

A Purple Martin does its best Emperor Palpatine impression. (Picture taken by Robinson Low on phone)

                Eventually the swallows returned with one goal in mind; take back the bird condo. They worked in a coordinated effort, some swooping in on the purple martin while others stood by and squawked angrily while keeping their distance. It was martin versus swallow, good versus bad, the dark side versus the light side of the force, Palpatine versus Luke Skywalker. In a climatic ending a single Red-winged Blackbird, Agelaius phoeniceus, swooped through the battle coming very close to the bird condo only to find its perch on a nearby shrub. This disturbance caused the purple martin to seemingly become overwhelmed and flee its perch on the condo. It was like the blackbird had been there the whole time, contemplating which side to fight for. Eventually it decided, and made its move, giving strength to the swallows. This blackbird’s name? Anakin Skywalker, otherwise known as Darth Vader. 

Avian Richness in Bellingham, WA

Avian Richness in Bellingham, WA

Adrianne M. Akmajian, Robinson R. Low, Melissa M. Oscarson

 Birds are one of many species vulnerable to increased human population growth and land use. Increasing land use destroys native habitat, which can negatively affect species richness. On the other hand, increased anthropogenic resources can add additional food and habitat for birds and lead to greater species richness in moderately disturbed areas (Lepczyk et al. 2008).

For our group project, we were interested in how urbanization and land use impacts avian richness in Bellingham, WA. Before we could answer that question, we had to learn to identify some birds. We looked up the most common birds sighted in Whatcom County in the month of May using an online, citizen-science database called eBird (ebird.org). This helped us narrow down what birds to expect in the area and what birds to learn. Then, it was time for some serious study. We took a list of over 50 bird species possible and over a three-week period tried to memorize songs, calls, and appearance of each.

A Google Earth view of our study site with land use categories labeled.

After learning as many of the birds as we could, we began our study. To do this study we used a method called a point-count. A point-count works by having an observer stand in one location and record all birds seen or hear in a given area away from the point and in a given amount of time (Ralph et al. 1993; Clergeau et al. 2001). We selected 24-points within a 1-mile area around the WWU campus. We tried to choose points that represented three broad categories of urbanization and land use: green sites that were primarily forested patches, residential sites in neighbors near campus, and high disturbance sites including areas with high traffic use, large areas of impermeable surface such as cement and blacktop, or areas of little to no vegetation. We expected that we would find the most bird species in our green sites and the least in the high disturbance sites, suggesting that the urbanization of Bellingham leads to decline in avian species richness.

We were also interested in how specific parts of the habitat influence species richness. For example, are birds more likely to be in more complex habitats, having large trees and both shrub and groundcover compared to areas with very little vegetation and a large cement parking lot? We had the students in our class help to go out and record both habitat and urbanization variables at each of our 24 sites. These variables included percent canopy, shrub, and ground cover and number of large trees, snags and nurse logs. The urbanization variables assess human use and included percent cement and blacktop and number of houses, buildings, and roads.

We conducted our bird counts over a four-day period from May 18^th to 21^st. At each point, we would spend 5-minutes recording all birds we saw and heard. We used digital recording devices to record bird calls so that we could go back and verify calls we were unsure or identify birds we missed in the field.

Percent cement or blacktop for all 24 sites.
 This variable described 40% of our data!

After the study period, it was time to analyze some data. Between all 24 sites, we identified 34 total bird species! We also found some interesting trends. As predicted, we found the most bird species at green sites compared to the high disturbance sites. We also found that some birds were only found in particular habitats. For example, orange-crowned warblers, Swainson’s thrush, and warbling vireos were only found at green sites. House sparrows and pigeons were common in residential and high disturbance areas, but never seen at green sites. Of all the habitat and urbanization variables we measured, only percent cement and number of large trees (>50 cm diameter) appeared to significantly influence species richness.

Based on our findings, we strongly encourage future city planners to continue to incorporate green areas in Bellingham. In particular, we believe it is important to preserve native and forested patches that are able to sustain the greater number of bird species.

The black-capped chickadee was one of the most
frequently sighted birds in our study and was observed
in all three of the land use categories.

Clergeau, P., J. Jokimaki and J.L. Savard.  2001.  Are urban bird communities influenced by the bird diversity of adjacent landscapes?  Journal of Applied Ecology 38:1122-1134.

Lepczyk, C.A., C.H. Flather, V.C. Radeloff, A.M. Pidgeon, R.B. Hammer and J. Liu.  2008.  Human impacts on regional avian diversity and abundance.  Conservation Biology 22(2):405-416.

Ralph, C.J., G.R. Geupel, P. Pyle, T.E. Martin and D.F. DeSante. 1993. Handbook of Field Methods for Monitoring Landbirds. USDA Forest Service, Pacific Southwest Research Station, Albany, California.USDA-PSW-Gen. Tech. Rept. 141.