Thread by @IBIS_journal

Today’s #ORNITHOLODAY is all about baby birds and how they grow up! #ornithology #GrowBirdGrow

Sarah Winnicki (personal account: @skwinnicki) will be tweeting fun facts about growing birds & details about her #PrairieBabies project on this account from 1400-1100 UTC, so keep checking in for more #ornithology #SciComm! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Keep an eye out for our hashtags #ORNITHOLODAY & #GrowBirdGrow. Please feel free to ask questions at any point throughout the day!

@skwinnicki My name is Sarah Winnicki (@skwinnicki)—I just finished my Master’s degree at Kansas State University (@kstatebio) in the lab of Dr. Alice Boyle (@birdfiddler). The research I’ll talk about for today’s #ORNITHOLODAY will be the research I completed in the #BoyleLab! #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler As you will (hopefully) see, I am very pumped about birds, especially baby birds and #cowbirds! I’m looking forward to continuing my research this fall as I start a PhD at @Illinois_Alma with @cowbirdlab and @Thomas_J_Benson #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson Before I dive right in, I’d first like to take you on a journey—the journey that led me to Kansas to study growing #PrairieBabies in the first place! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson I (@skwinnicki) was a biology undergraduate student at @DenisonJobs. As a lifelong birder (trained under the wings of the amazing @OYBC), I knew I wanted to study birds but didn’t have many opportunities to do so at my small college. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson @DenisonJobs @OYBC In the United States undergraduates have the neat opportunity to participate in the @NSF’s Research Experience for Undergraduates (REU) program, which pairs students with universities around the country for a 10-week summer research experience #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson @DenisonJobs @OYBC @NSF I joined the #BoyleLab for an REU program in the summer of 2014, traveling to Kansas for the first time to study Grasshopper Sparrows (Ammodramus savannarum) on the beautiful Konza Prairie (@KonzaLTER, @KonzaDirector). #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson @DenisonJobs @OYBC @NSF @KonzaLTER @KonzaDirector I didn’t go to Konza with the intent of studying growing babies at all. Instead I was interested in why the sparrows chose to establish their breeding territories in little clumps across the prairie.

[darkest blue=most sparrows]

#ORNITHOLODAY #GrowBirdGrow

@skwinnicki @kstatebio @birdfiddler @Illinois_Alma @cowbirdlab @Thomas_J_Benson @DenisonJobs @OYBC @NSF @KonzaLTER @KonzaDirector I wanted to know if these little bird clumps allowed the sparrows to nest more successfully than they’d be if they spread out their territories, so I helped the #BoyleLab #KonzaCrew find nests and monitor nests. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Finding sparrow nests is a really big pain! @KonzaLTER is a beautiful remnant tallgrass prairie, full of thick grass in which to build tiny, concealed ground nests. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @KonzaLTER Can you see the sparrow eggs in this picture? I took this photo a mere 5cm away from the front of the nest cup! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki The best way to find these nests is by “flushing,” mom, forcing her to temporarily leave the nest and reveal its location. We maximize the likelihood of flushing parents by dragging a big weighted rope across the prairie: #ORNITHOLODAY #GrowBirdGrow

@skwinnicki We found the nests and returned every two days to check them and make sure they were still active. Right before the babies (called “nestlings”) are able to leave the nest we pull them out to take measurements. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki We measured each nestlings’ tarsus bone (our ankle bone, which in a perching bird is the bottom portion of their visible “leg”), wing length, and mass. We took a tiny blood sample from their wings from which I could extract DNA. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Finally, we gave each nestling an aluminum leg band (also known as a “ring”) with a unique number code. That way, if these birds returned to @KonzaLTER in later years we would know they were one of our nestlings! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Fun side note (to this already long tangent about my journey to #PrairieBabies), Grasshopper Sparrow fledglings (what we call nestlings when they leave the nest, or fledge) are about the size of actual grasshoppers at this site! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki The more nestlings I measured, the more I started to realize that despite all being the same age (only 6 days old!) and the same species, at the same location, these birds could look really different! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Some were larger than others--weighing more or having longer wings or tarsi (legs). Some had really well developed feathers and seemed ready to leave the nest, while others were almost naked. These sparrows are siblings of the same age!! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki These observations were intriguing but not really my focus—I had 10 weeks and I needed to know why the adult birds chose to put their territories in clumps! I know y’all are here to learn about how birds #GrowBirdGrow, so I’ll spare you the details. #ORNITHOLODAY #ornithology

@skwinnicki Basically, after a summer of looking at behavior, genetics, & other hypothesized drivers of territory aggregation I had no good answer. So, the next summer, with @birdfiddler’s help, I got another @NSF REU to return to @KonzaLTER and collect more data. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki @birdfiddler @NSF @KonzaLTER If you’re intrigued by the sparrow aggregation question, you’re in luck! Our manuscript is in review and will hopefully be out soon—follow me (@skwinnicki) or my coauthors (@wayfaringwilly, @SteffMunguia, and @birdfiddler) for more news! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki When it came time to graduate from @DenisonJobs I couldn’t help but be intrigued by my strange observations of sparrow growth differences. With the help of the @NSF_GRFP funding program, I returned to @kstatebio and the #BoyleLab to start my MS. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki So that (finally) brings us to bird growth and #PrairieBabies. Skip over all the hero’s journey parts? Basically, prairie sparrows of the same species in the same location appear to grow at different rates. I want to know why! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Animal growth is a really neat study topic! Growth patterns are the result of evolution, genetics, and the current environment, and these growth patterns affect everything from survival to reproduction to behavior. How? #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Imagine your siblings, or a friends’ siblings. Did all of them grow up the exact same way? Were they all the same height by age 5, or did they all lose their teeth at the same time? Individual humans vary in their patterns of growth and development. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Birds vary in their patterns of growth and development too! Different types of birds grow in remarkably different ways… #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki When a duckling hatches, it already has its feathers and is quite developed! They stick around in the nest for a few hours to dry up and get used to standing, and then they follow a parent to water. [Photo licensed creative commons] #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Ducklings are what we call “precocial,” because they hatch from the egg well developed and require little parental care—their parents guide them around and keep them safe, but otherwise the ducklings are able to feed and fend for themselves! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki There are even birds that we term “superprecocial”—they hatch so well-developed they require no post-hatch care at all! Mound-builders, a group of turkey-like birds in Australasia, can fly and pursue prey on the day that they hatch! [Image CC licensed] #ORNITHOLODAY #GrowBirdGrow

@skwinnicki On the other end of the spectrum are the birds we call “altricial.” They are the opposite—when they hatch from the egg they are not very well developed, and they are completely reliant on their parents for food and care. Here's a hatching meadowlark: #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Whew sorry it took me so long to update the #ORNITHOLODAY thread-- my internet connection did *not* like the size of that video file!

@skwinnicki So, we wanted to study bird growth. Did we choose to study cute little ducklings? Nah—we choose to study the ugly pink sparrow babies! #PrairieBabies #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, different types of birds can grow up and develop in different ways. If mound-builders can manage to lay eggs that grow really quickly, why don’t all birds do that? Why do we see this variation at all? #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki It all comes down to the ways the birds invest their energy. The eggs of precocial birds like ducks are large & full of nutrients (that’s why folks eat them!)—they have as much as twice as many calories for their size compared to altricial birds’ eggs! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki In order to lay this big egg, mom has to have access to a lot of food before she lays the egg. In contrast, altricial bird mothers, laying smaller eggs, don’t need to have as much food beforehand. They need to find that food after hatch! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Bird parents also need to balance the risk of predators eating their young. By staying in the nest, altricial nestlings become “sitting ducks,” unable to escape nest predators, yet once they leave they can often easily escape on their own. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki In contrast, precocial birds like ducklings can (ironically) avoid being sitting ducks by leaving the nest more quickly, yet outside the nest they will be at the mercy of predators for weeks before they are capable of flying away. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki In conclusion, different types of birds juggle the constraints of variations in food availability and predator risk in different ways, evolving strategies that result in broad species-level variation in growth and development! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, ducks and sparrows develop in different ways—you're saying "Sarah, duh, we’ve known this forever!" But just like individual human siblings, even members of the same bird species can grow up and develop in different ways! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Individuals can vary in their overall growth rate—as previously mentioned, even at our single tiny (35 square kilometer) slice of prairie in Kansas, Grasshopper Sparrows appeared to be growing at different rates. #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki Perhaps instead of growing more quickly overall, the birds can grow individual body parts at different rates. Some may allocate more energy to the growth of their wings, so they can fly away earlier, but at the expense of the growth of other body parts #ORNITHOLODAY #GrowBirdGrow

@skwinnicki For example, Sofaer et al. found that Orange-crowned Warblers growing up in Alaska grew their feathers faster than the same species growing up in California. (Check out this busy Orange-crowned Warbler parent I found in Alaska this summer!) #ORNITHOLODAY #GrowBirdGrow

@skwinnicki These Alaskan warblers grew their feathers faster, but were smaller overall than the California warblers that grew their feathers more slowly. This ultimately shifted their body proportions. We call this “allometric growth.” #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki How might these different growth patterns (faster overall growth, allometric growth) come about in individual birds? #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Individual variation is often the result of genetic variability—each nestling has different genes, therefore the variation in genes that control different aspects of growth result in variation in growth patterns. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Yet we know that development is not only the result of nature (genetics) but also nurture—the environment in which these birds develop! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Individual bird eggs can vary in quality—some have more nutrients for the developing chick, or different levels of hormones that ultimately affect the bird’s growth both inside and outside the egg!

[failed egg showing inside through membrane]
#ORNITHOLODAY #GrowBirdGrow

@skwinnicki These differences can be the result of differences in egg-laying females’ body condition and environment (how much food is available, how much stress she is under due to predators, weather, or disturbance, etc.) #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki For birds that rely on parents after they hatch (my altricial birds!) growth after hatch can be dependent on how much food they receive from parents, the quality of that food, the nestlings’ stress due to disturbance, etc. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Understanding the different mechanisms that lead to variation in individual birds’ growth is complicated! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki In humans, growth variation may not have many consequences. Growing tall quickly may influence your chances at making the youth basketball team, but will (hopefully) not influence your future survival or reproductive success. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki But baby birds are not nearly as successful as baby humans—in my study system, as few as 10% of eggs hatch into nestlings that manage to leave the nest before being eaten.

Here's a Speckled Kingsnake at one of our Dickcissel nests: #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki My colleague @inkliizii tracked the few surviving nestlings once they left the nest. The majority of those survivors were eaten within 24 hours—only one made it to the end of his tracking period! More info: animalecologyinfocus.com/2018/08/31/i-s…

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki It appears predation is a huge selection pressure in this system. Could these sparrows’ growth be influenced by predation risk in the past (parents' fear), the present (current behavioral responses), and future ( chance of post-fledge survival)? #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Birds that grow very quickly may be able to escape predators at an earlier age, increasing their chances of survival, but this comes at a cost—they need lots of energy from food, a large burden on their busy parents. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Therefore, in areas with lots of predators, we hypothesize that parent birds would bring more food to their offspring, allowing them to grow more quickly to increase their likelihood of survival. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Of course, food resources are not unlimited—it takes a lot of work for a parent to find food and bring it back to the nest! Plus, most birds do not have claim to all of the food their parents bring—they also have to compete with pesky siblings! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki We hypothesized that birds in more competitive nests (more siblings, a.k.a. larger broods) may not be able to grow as quickly, because they would be food-limited due to nestling competition #ORNITHOLOGY #GrowBirdGrow #ornithology

@skwinnicki The birds may also change their allometric growth patterns—perhaps growing their wings earlier (at the expense of the growth of other body parts) to be able to better escape from predators at an earlier age. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, could sparrow growth patterns be a response to predation risk, brood size, and food availability? Interesting stuff, but I’ve been holding out on you by failing to mention the coolest part of our study system: the Brown-headed Cowbird! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Brown-headed Cowbirds (Molothrus ater) are brood parasites. This means that they their eggs in other birds’ nests, forcing those birds to raise their babies.

This nest should only have two blue Dickcissel eggs, not 5 #cowbirds

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Many, many species parasitize nests—my sparrows do it to each other! This helps them spread their eggs among “more baskets,” helping ensure that some of their offspring make it even if their own nest fails. We call this “conspecific brood parasitism.” #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Some species parasitize other bird species’ nests. Those species may be able to raise the young just fine--for example, ducks will do this, since ducklings just need fancy adult chaperones. We call this “heterospecific brood parasitism.” #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki This behavior may be very rare in some species but it is cool when we observe it! Check out this odd Sandhill Crane-Canada Goose family! audubon.org/news/this-sand…

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki I don’t know for sure if this family was the result of parasitism or if the cranes adopted a recently hatched goose, but I always need more excuses to share this article because it is adorable. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki But cowbirds are special. No Brown-headed Cowbird makes her own nest at all—they exclusively parasitize other species nests! So, they are not only heterospecific brood parasites—they are “obligate heterospecific brood parasites.” #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Brown-headed Cowbirds aren’t the only obligate brood parasites—there are other species of cowbirds in South and Central America, plus African indigobirds, whydahs, and honeyguides, and even a species of duck! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki [There are also some wonderful examples of brood parasitism in insects and fish (as my fish-loving committee member @MichiTobler is always reminding me) but as this is an #ornithology thread and birds are better anyway, I’ll stick with birds #BirdsVsFish #BirdsVsFishes]

@skwinnicki @michitobler But perhaps the most common example of obligate brood parasitism rests with the Old World cuckoos—these birds almost always force out their hosts’ eggs, leaving the host to care for a single, often larger nestling. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Brown-headed Cowbirds often remove a single host egg when they lay their own, but they often leave the rest, resulting in mixed-species nests of competing nestlings.

Big red mouth=cowbird
Small yellow mouth= Dickcissel host

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Brown-headed Cowbirds are super neat, so here’s a short tangent about how cool they are. From here on out, when I say “cowbirds” I mean the Brown-headed kind. The others are super cool too (check them all out!) but these are *my* #cowbirds. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki I put most of these cool facts in a thread/rant on my personal Twitter account, so if you are looking for citations for these facts please check out that thread:

https://twitter.com/skwinnicki/status/1122671477663457285

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Cowbirds parasitize 220+ species of birds in North America (mostly songbirds, but they sometimes mess up and parasitize other species, like ducks). That makes them “generalist obligate heterospecific brood parasites” for those keeping score at home #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Although fossil records indicate that their range spanned the continental United States during the Pleistocene, their range was constrained to the Great Plains grassland region in the center of the continent for the last few thousand years. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki They often forage near our native bison ungulates, so colonizers initially called them “bison birds.” It was thought that they evolved parasitism to follow bison around, as bison moved enough the birds couldn’t stop to tend a nest. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki …but it turns out bison likely didn’t move as much as we think they do, and cowbirds as a clade evolved their parasitism strategy in South America without bison. Nice story, but remember, none of the other parasites needed bison to evolve! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki The native hosts of the cowbirds have evolved some really neat strategies to combat the presence of #cowbirds. They hide and defend nests, knock out cowbird eggs or build over them, preferentially feed their own nestlings, etc. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Yet some native hosts take care of the baby cowbirds anyway. Why? It may be less costly than rejecting eggs, which could result in catastrophe if the bird rejects or breaks its own eggs. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki There’s also the potential that these cowbirds are more attentive parents than they first appear. They may check in on their eggs and retaliate if the hosts do not do a good job raising them! sciencemag.org/news/2016/12/t…

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki I didn’t study this “mafia hypothesis” at our site, but I have seen cowbird adults kill host nestlings in nests where cowbird eggs failed to hatch or cowbird nestlings died. Gruesome circle of life! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Many humans find #cowbirds’ breeding strategies morally incorrect, and go out of their way to remove cowbird eggs or nestlings from the nest. This can be a real problem for the host parents! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki If the #cowbirds come back and find their babies absent they may retaliate and remove the hosts’ offspring. Even if they don’t come back, the missing eggs/nestlings may convince the hosts that there’s a predator nearby, so they’ll abandon their nest. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Native cowbird hosts have evolved strategies to deal with them, so don’t stress out the host parents by messing with their nests! Leave cowbird eggs/nestlings alone!

[This message message courtesy of an accused “cowbird apologist”]

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Native cowbird hosts appear to have their act together—they can raise both cowbirds and their own nestlings. But cowbirds have started to interact with a whole new set of host species. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki As colonizers opened up the forests of the eastern and western coasts of the continent, the grassland-associated cowbirds expanded their range, interacting with new species of host that hadn’t evolved responses to parasitism. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Cowbird nestling competition has been very detrimental to species that are already threatened due to human-caused habitat loss, like the Kirtland’s Warbler. To save this endangered species, researchers killed hundreds of adult cowbirds. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki It worked! Kirtland’s Warblers are starting to rebound. But note that even here, researchers weren’t removing cowbird eggs. They were removing adults with special permits (as cowbird adults, eggs, and nestlings are all federally protected). #ORNITHOLODAY #GrowBirdGrow

@skwinnicki To conclude this tangent, #cowbirds are super cool! Think of how much information they must process to successfully sync their reproduction with host species.’ Don’t kill them unless you have permits to do so! Become a cowbird lover/apologist like me! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Back to project #PrairieBabies. Grasshopper Sparrows at our study site are frequently parasitized by cowbirds. The cowbirds are as much as double the size of the sparrows. How does having a gigantic competitor affect sparrow growth? #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki We hypothesized that sparrows may be out-competed by cowbirds and grow more slowly. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Or, they might allocate their energy in a way that focuses on preparing them for battle with the hungry cowbird nestlings. Maybe they grow their mouths faster than other body parts, to get more food. Or their legs, so they can stand taller to beg. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki But cowbirds may not only directly compete with nestlings for food. They beg really, really frequently. Check out how much time the cowbird (red mouth with white rim) has its mouth open relative to the Dickcissel hosts (yellow rim mouth). #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki This begging may actually encourage host parents to bring more food to the nest overall. The host nestlings may therefore actually get more food when cowbirds are present, assuming parents can keep up with the demand! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki That begging may come at a cost for the whole nest, though. The loud begging calls or the parents’ continual visits to the nest with food may attract more predators to the nest… therefore, #cowbirds may increase predation risk. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, how do cowbirds affect growth? We hypothesized that they’d do it directly (through competition) and indirectly (by altering food availability and predator risk). That, in essence, is our project #PrairieBabies! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki We spent two years collecting evidence to test these relationships with not only developing Grasshopper Sparrow babies but also two other species—Eastern Meadowlarks and Dickcissels. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Eastern Meadowlarks are as much as double the size of cowbirds. Look at that sad little cowbird (tiny one on the right). We expected that these big meadowlarks wouldn’t suffer as much from cowbird competition because of their size. #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki Dickcissels are the same size as cowbirds and their favorite host. At @KonzaLTER, @Bram_Verheijen found one Dickcissel nest with nine (9!!) cowbird eggs.

Dickcissels have yellow-rimmed beaks, cowbirds have white-rimmed beaks.

#ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki We went out to the prairie seven days a week, looking for host nests in the tallgrass by dragging a rope or by waiting (not-so-)patiently for the bird to drop down to its nest with food.

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki We visited nests every other day, taking a whole suite of measurements on two of the hosts (chosen at random and identified with Sharpie marks) & one of the cowbirds. We measured bone growth, wing growth, eye & muscle development, mass… #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki We even put some of the birds inside our fancy quantitative magnetic resonance machine, a big MRI-like machine that we haul out to the prairie in a trailer. It allows us to measure the birds’ fat and muscle mass without hurting them! #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki At a subset of the nests, we went through the painstaking process of setting up secretive nest cameras. We put little spy cams at the nest and ran a cord underground to a DVR and battery box nearby. We had to hide it from predators, cows, and bison! #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Over two summers we recorded over 8 months of continuous (24/7) footage, which we used to identify predators and count the number of times parents brought food to the nestlings. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki We found lots of cute videos of parents taking care of their babies, like these Grasshopper Sparrows:

(Sorry I'm linking instead of embedding videos, my internet is choking at the moment)

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki We watched birds leave the nest, like this meadowlark that ultimately decides to jump right back in and stick around for a few more hours



#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki But the most exciting parts of the footage featured predation events. We saw so many predators eating our nestlings! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki In the first year, we only saw snakes. Just two species: kingsnakes and racers!



#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki In the second year we were hit by a horrible drought and the predator community shifted to include coyotes, ground squirrels, skunks, ants, and owls.



#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki We even caught #cowbirds on camera destroying nests three different times!



#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki If you’re interested in the neat drought-related predator community shifts, keep an eye out for @inkliizii, @AustinRoe12, @birdfiddler, and my manuscript about it, coming soon to a journal near you! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki We were interested in not only the realized predation (a.k.a. if the birds were eaten) but also the fear of predation that the parents might experience, as that could change their resource allocation and feeding behavior. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki We can’t tell exactly what the birds are experiencing, but we decided that more predators=more fear. We graphed all of the nests that were depredated and made a heat map of “risk” as the number of depredated nests/ha. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki [Me then: wow can I really fill nine hours with #PrairieBabies material for this #ORNITHOLODAY? I really need to spread this out!

Me now: Oh boy, how fast can I tweet this stuff before @IBIS_journal takes away my login?]

@skwinnicki Before I dig into our results, I first have to acknowledge that this project, like most #science projects, was a HUGE undertaking requiring thousands of people-hours and lots of funding. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki In addition to my @NSF funding, we were supported by @kstatebio, @sunsetzoo, @KonzaLTER, and @SWANMeeting. Our camera parts came from @BKSandercock

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Over two years I was joined by an amazing crew of undergraduate field technicians, including @GreshamJoanna, @marykatewilcox, @DirtyCole21, and many others. Here’s the 2017 #PrairieBabies crew:

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki @GreshamJoanna @marykatewilcox @DirtyCole21 I’m especially thankful that #BoyleLab alum @inkliizii came back to lead my crew during the second summer so I could focus on writing! Here’s the 2018 #PrairieBabies crew in our custom #BoyleLab tie-dye:

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki @GreshamJoanna @marykatewilcox @DirtyCole21 In addition to the wonderful field crews, I was lucky to have over a dozen undergraduates helping watch camera footage! It takes a very long time to watch that many hours of #PrairieBabies footage! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Our results are quite preliminary (I just defended my thesis, so we will polish this story up in the next few months before we submit it) but we were quite surprised, to say the least! #PrairieBabies #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Overall we found hundreds of nests and I took over >800 sets of measurements on 316 nestlings. So many babies!! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Overall about 50% of the nests were parasitized, but that was not evenly spread among the host species. Cowbirds parasitized 25% of meadowlark nests (big host), 67% of Dickcissel nests (medium host), and 37% of sparrow nests (small hosts). #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Predation was also high, as expected. Our models estimate that a mere 20% of meadowlark nests, 20% of Dickcissel nests, and 13% of sparrow nests managed to fledge a single nestling. Here's a milksnake eating a hatch-day sparrow #PrairieBabies #ORNITHOLODAY #GrowBirdGrow

@skwinnicki These birds all grew very quickly—if human children grew as quickly as our sparrow nestlings, we’d be four foot tall and weigh 70lb when we were only 7 days old!

[Someone help me find this photographer please]

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki These birds also left the nest very early—the Dickcissels and sparrows went from egg to fledgling in 7 days! The meadowlarks took a bit longer (11 days). Some sparrows even successfully left the nest when they were 4 days old! #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki While we haven’t performed our analyses comparing these metrics to the growth rates/fledge age of these species in other areas, we suspect that our hosts are growing much faster & leaving the nest much earlier than expected #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Even though these birds appear to be on an accelerated timeline (and, again, are the species in the same place/time) their growth varies. An individual meadowlark may be 50% larger than another meadowlark of the same age nearby. Here, tarsi lengths: #ORNITHOLODAY #GrowBirdGrow

@skwinnicki We plugged all of these data into some fancy statistical models (nested longitudinal structural equation models, for you stats nerds) to see which relationships between variables were the strongest! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki It turns out that each host responds to #cowbirds in slightly different ways. So far so good, right? We expected cowbirds to have the smallest impact on the large meadowlarks, after all… #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki And that mostly held up! Cowbirds didn"t have a large impact on meadowlark growth but predation did—scared meadowlarks gained mass faster than other body parts. Maybe because small predators can’t eat chunky nestlings?

#ORNITHOLODAY #GrowBirdGrow

@skwinnicki Interestingly, though, meadowlarks with cowbird “siblings” left the nest days earlier than the meadowlarks that were not parasitized, perhaps to escape the competition (even though we didn’t see any measurable effects of competition?) #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki If #cowbirds are affecting the meadowlarks enough to drive them out of the nest days early, surely the smaller host species must experience even more dramatic effects of cowbirds on growth and development, right? Right???

[cowbird baby]

#ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Dickcissels (medium-sized host), exhibited reduced growth in the presence of cowbirds overall, but only if there was more than 1 cowbird present. They seem to be able to cope with just 1! Yet, this competition did not change their fledge age at all #ORNITHOLODAY #GrowBirdGrow

@skwinnicki Sparrows, the smallest host, are smaller than the cowbird. So much so that previous studies about cowbird hosts have not even bothered to look at the growth of hosts as small as these sparrows, assuming that they’d be too small to survive #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Yet our sparrows do survive when cowbirds are in the nest. And, better yet, cowbirds have no measurable impact on sparrow growth and development. No cowbirds in the nest, three cowbirds in the nest… it makes no difference to sparrow babies. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki How do they pull this off? Well, the parents may increase the amount of food they bring, but unfortunately we don’t have enough data to make any strong conclusions about that #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Sparrows and Dickcissels, like meadowlarks, appear to respond more strongly to predation risk than parasitism. Sparrows and Dickcissels grew their tarsi (legs) faster relative to their overall body size in areas with lots of predators #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki [Side note: real shout-out to this Yellow-bellied Racer that hung out next to me for a half hour as I took his photo over and over]

@skwinnicki Having strong little legs may help the nestlings run away from nest predators before they are able to fly #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki So what did this portion of project #PrairieBabies teach us about bird growth and #cowbirds? Cowbirds are everywhere at this site, yet these native hosts seem to have found strategies to raise their young with little cost to the nestlings #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki Perhaps a long history of parasitism in this region allowed these birds to adapt—maybe that’s why they grow so quickly and fledge so early overall! We’ll explore this next by comparing our data to data collaborators gathered at other sites. #ORNITHOLODAY #GrowBirdGrow

@skwinnicki It is really cool to find that they respond to predation, though! We knew that birds’ growth changed when parents were scared (see Coslovsky and Richner 2011) but those studies experimentally manipulated perceived predation risk #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki In other words, they made the parents more scared by convincing them that there were more predators nearby! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki That is awesome work, but it is also cool that our birds responded to naturally-occurring variation in predation risk! Nestling growth is altered by variation at the nest site level! I think this is totally rad. #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki We also decided to look at cowbird growth! After all, #cowbirds experience a much wider range of brood sizes, food availabilities, and predation risks across all their host species than do the nestlings of a given host species #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, we ran similar models, looking at the effects of host species, food delivery rate, and predation risk on variation in cowbird growth. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Surely, growing up with different size competitors, different amounts of food, and different predation risks affects cowbird growth? Well, so far we really don’t see any evidence that it does. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki This is particularly surprising because, remember, the host nestlings in the exact same nests are responding to nest-level variation in predation risk, but their cowbird “siblings” are not. #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Maybe the grassland hosts’ predation risk and provisioning rate just don’t vary enough for the cowbirds (especially relative to their larger range of encountered predation risks and provisioning rates). #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Maybe female cowbirds cannot make the same decisions regarding predation risk at a single nest (and allocate nutrients/hormones to her egg accordingly) because she is flying all over the wide prairie looking for nests constantly #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki Remember that all these results are preliminary, but I think they are super cool! Birds responding to environmental drivers at different scales despite sharing the same nest? Hosts able to grow just fine in the presence of #cowbirds? #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki I’m really excited to dig into these data a little bit more—look at provisioning behavior a little more closely, compare nestlings between sites, etc. So, keep an eye out for the rest of this #PrairieBabies story! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki So, in conclusion to a very long #ORNITHOLODAY #GrowBirdGrow thread, individual organisms exhibit variation in their growth rates and development strategies. This variation may be, in part, individual responses to environmental drivers #ornithology

@skwinnicki At our study site in Kansas (@KonzaLTER), grassland birds’ growth and development can vary dramatically among and within species. This variation is most closely tied to the risk of predators at the site #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki Birds can respond to predation risk at the nest site itself (a very small area!), and this appears to matter more than the very high rates of cowbird parasitism at the site.
[This Dickcissel nest has only cowbird eggs!]

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki And surprisingly, cowbirds developing in the same nests respond to these drivers in different ways! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Why does this matter? Humans are dramatically changing species’ habitats. Even in this pristine prairie, we see very quick habitat degradation when the site is unburned for even a few years. [left: burned this year, right: 4 years ago] #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki If something as specific as the risk of predators in a 100 square meter area can produce a measurable effect on the growth and develop of nestlings, what will our dramatic anthropogenic changes do to developing birds? #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki What effect will these changes in growth and development have on the birds’ survival and future reproduction? This is especially important for these species, as they’re all threatened and experiencing declines as high as 2%/year #ORNITHOLODAY #GrowBirdGrow #PrairieBabies

@skwinnicki Plus #cowbirds threaten new host species. Understanding the ways in which native hosts evolved to combat this threat gives us new insight into the coevolution between hosts and parasites! #ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies

@skwinnicki Want to learn more about this system? Contact me (@skwinnicki, sarahwinnicki.com) and/or watch for updates under our #PrairieBabies handle! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki The #BoyleLab is also full of some really cool other people working in this system that you can follow! Of course, our fearless leader @birdfiddler! Check out her website aliceboyle.net for more information about all of this! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki @birdfiddler Former PhD student (and current Denali National Park biologist and leader of the popular #WhosePoo game) Emily Williams (@wayfaringwilly) actually posted a neat thread about some of her work at @KonzaLTER just today!

https://twitter.com/wayfaringwilly/status/1161658051306250240

#ORNITHOLODAY #GrowBirdGrow

@skwinnicki @birdfiddler @wayfaringwilly @KonzaLTER Current PhD student Katy Silber (@katy_silbird) has just wrapped up her first field season. Watch out for big things coming from her in the next few months/years! #ORNITHOLODAY #GrowBirdGrow #ornithology #BoyleLab

@skwinnicki @birdfiddler @wayfaringwilly @KonzaLTER @katy_silbird Current MSc student Dylan Smith (@inkliizii) is using big citizen science data and historical @KonzaLTER data to see how grassland birds respond to changes in climate! Give him a follow! #ORNITHOLODAY #GrowBirdGrow #ornithology #BoyleLab

@skwinnicki @birdfiddler @wayfaringwilly @KonzaLTER @katy_silbird @inkliizii Current undergraduate Joanna Gresham (@GreshamJoanna) just wrapped up a neat experiment about the effect of changing nest orientation (which direction the nest opening faces). I’m sure she’d love to talk about how cows can wreck experiments! #ORNITHOLODAY #GrowBirdGrow #BoyleLab

@skwinnicki @birdfiddler @wayfaringwilly @KonzaLTER @katy_silbird @inkliizii @GreshamJoanna The last current #BoyleLab student, Elsie Shogren (@e_shogren), doesn’t study grasslands at all but rather works in the rainforest studying the interactions between sexual selection and natural selection in dancing manakins! #ORNITHOLODAY #GrowBirdGrow #ornithology #BoyleLab

@skwinnicki Thank you all for tuning in/reading this far down in this massive thread (for some reason) and thanks @IBIS_journal and @stevedudley_ for the invitation to flood everyone’s feed with #PrairieBabies all day! #ORNITHOLODAY #GrowBirdGrow #ornithology

@skwinnicki @stevedudley_ If you have any questions please don't hesitate to contact me!

I’ll leave you with one last parting #cowbird!

#ORNITHOLODAY #GrowBirdGrow #ornithology #PrairieBabies