Blue Jays Research Articles

Widespread Rapid Quenching at Cosmic Noon Revealed by JWST Deep Spectroscopy

Massive quiescent galaxies in the young Universe are expected to be quenched rapidly, but it is unclear whether they all experience starbursts before quenching and what physical mechanism drives rapid quenching. We study 14 massive quiescent galaxies ( log(M⋆/M⊙)>10 ) at z ∼ 2 selected from a representative sample of the Blue Jay survey. We reconstruct their star formation histories (SFHs) by fitting spectral energy distribution models to the JWST/NIRSpec R ∼ 1000 spectra. We find that massive quiescent galaxies can be split into three categories with roughly equal numbers of galaxies according to their SFHs: (1) relatively old galaxies quenched at early epochs; (2) galaxies that are rapidly and recently quenched after a flat or bursty formation history (depending on the assumed prior); and (3) galaxies that are rapidly and recently quenched after a major starburst. Most recently quenched galaxies show neutral gas outflows, probed by blueshifted Na i D absorption, and ionized gas emission, with line ratios consistent with active galactic nucleus (AGN) diagnostics. This suggests that AGN activity drives multiphase gas outflows, leading to rapid quenching. By tracing back the SFHs of the entire sample, we predict the number density of massive quiescent galaxies at z = 4–6: n = (1.5–6.0) × 10−5 Mpc−3. The two old massive quiescent galaxies in our sample appear to have extremely early formation and quenching (z ≳ 6) and are possibly descendants of early post-starbursts at z > 3. These galaxies still show neutral gas reservoirs and weak Hα emission, perhaps because the ejective AGN feedback that caused rapid quenching has weakened over time.

Pigeons' (Columba livia) intertemporal choice in binary-choice and patch-leaving contexts.

Typical approaches to study self-control present subjects with a simultaneous choice between a larger-later (LL) reinforcer and a smaller-sooner (SS) reinforcer. In contrast, in patch-leaving tasks, subjects choose between staying at a patch for an SS (or LL) reinforcer and leaving for an LL (or SS) reinforcer. Previous studies show that blue jays, monkeys, humans, and rats prefer the SS reinforcer in binary-choice tasks, whereas the same subjects prefer the LL reinforcer in equivalent patch-leaving tasks. The current study systematically replicated this research using pigeons. Six pigeons responded in a binary-choice task and in two patch-leaving tasks in which staying led to an LL (Patch-L) or SS (Patch-S) reinforcer. Across conditions, the SS reinforcer delay varied from 5 to 55 s; the LL reinforcer delay was always 60 s. In binary-choice conditions, subjects preferred the SS reinforcer. In Patch-L and Patch-S conditions, subjects preferred the LL and SS reinforcer, respectively, reflecting a bias to stay at the patch. This bias persisted when the stay response was more effortful and when the delays to both reinforcers were equal. This may reflect a species-specific win-stay bias and the differential consequences of staying (which led to a stimulus signaling food) versus leaving (which led to a stimulus never associated with food). Thus, we propose a conditioned-reinforcement account of intertemporal choice in patch-leaving contexts. We suggest several avenues for further investigations of the mechanisms underlying intertemporal choice in different contexts and question the economic equivalence of the operant and patch-leaving procedures. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Slow and steady: auditory features for discriminating animal vocalizations.

We propose that listeners can use temporal regularities - spectro-temporal correlations that change smoothly over time - to discriminate animal vocalizations within and between species. To test this idea, we used Slow Feature Analysis (SFA) to find the most temporally regular components of vocalizations from birds (blue jay, house finch, American yellow warbler, and great blue heron), humans (English speakers), and rhesus macaques. We projected vocalizations into the learned feature space and tested intra-class (same speaker/species) and inter-class (different speakers/species) auditory discrimination by a trained classifier. We found that: 1) Vocalization discrimination was excellent (> 95%) in all cases; 2) Performance depended primarily on the ~10 most temporally regular features; 3) Most vocalizations are dominated by ~10 features with high temporal regularity; and 4) These regular features are highly correlated with the most predictable components of animal sounds.

Escalation by duplication: Milkweed bug trumps Monarch butterfly.

The iconic Monarch butterfly is probably the best-known example of chemical defence against predation, as pictures of vomiting naive blue jays in countless textbooks vividly illustrate. Larvae of the butterfly take up toxic cardiac glycosides from their milkweed hostplants and carry them over to the adult stage. These compounds (cardiotonic steroids, including cardenolides and bufadienolides) inhibit the animal transmembrane sodium-potassium ATPase (Na,K-ATPase), but the Monarch enzyme resists this inhibition thanks to amino acid substitutions in its catalytic alpha-subunit. Some birds also have substitutions and can feast on cardiac glycoside-sequestering insects with impunity. A flurry of recent work has shown how the alpha-subunit gene has been duplicated multiple times in separate insect lineages specializing in cardiac glycoside-producing plants. In this issue of Molecular Ecology, Herbertz etal. toss the beta-subunit into the mix, by expressing all nine combinations of three alpha- and three beta-subunits of the milkweed bug Na,K-ATPase and testing their response to a cardenolide from the hostplant. The findings suggest that the diversification and subfunctionalization of genes allow milkweed bugs to balance trade-offs between resistance towards sequestered host plant toxins that protect the bugs from predators, and physiological costs in terms of Na,K-ATPase activity.

Detection of Accretion Shelves Out to the Virial Radius of a Low-mass Galaxy with JWST

We report the serendipitous discovery of an extended stellar halo surrounding the low-mass galaxy Ark 227 (M * = 5 × 109 M ⊙; d = 35 Mpc) in deep JWST NIRCam imaging from the Blue Jay Survey. The F200W–F444W color provides robust star–galaxy separation, enabling the identification of stars at very low density. By combining resolved stars at large galactocentric distances with diffuse emission from NIRCam and Dragonfly imaging at smaller distances, we trace the surface-brightness and color profiles of this galaxy over the entire extent of its predicted dark matter halo, from 0.1 to 100 kpc. Controlled N-body simulations have predicted that minor mergers create “accretion shelves” in the surface-brightness profile at large radius. We observe such a feature in Ark 227 at 10–20 kpc, which, according to models, could be caused by a merger with total mass ratio 1:10. The metallicity declines over this radial range, further supporting the minor merger scenario. There is tentative evidence of a second shelf at μ V ≈ 35 mag arcsec−2 extending from 50 to 100 kpc, along with a corresponding drop in metallicity. The stellar mass in this outermost envelope is ≈107 M ⊙. These results suggest that Ark 227 experienced multiple mergers with a spectrum of lower-mass galaxies—a scenario that is broadly consistent with the hierarchical growth of structure in a cold-dark-matter-dominated universe. Finally, we identify an ultra-faint dwarf associated with Ark 227 with M * ≈ 105 M ⊙ and μ V,e = 28.1 mag arcsec−2, demonstrating that JWST is capable of detecting very-low-mass dwarfs to distances of at least ∼30 Mpc.

“Be a Good Fan During the Good, the Bad, and Even the Ugly”: Exploring Cultural Boundaries Through Sport Fan Discourses on Twitter

While sport fandom can be assumed to be inclusive, a deeper exploration of discourses around fandom exposes alternative perspectives. Using the frameworks of cultural boundaries and critical discourse studies, we explored how sport fans use Twitter to create, maintain, and transform cultural boundaries of sport fandom. We used tweets from a season of the Toronto Blue Jays baseball team as a case. Data were collected via Visual Twitter Analytics software focusing on tweets containing #LetsRise and #BlueJays. From the larger data set, we selected 172 tweets to examine using critical discourse analysis and ideological structures of discourse. Findings demonstrate that discourses of loyalty, consumption, and unity have plural meanings and are used to draw boundaries that are simultaneously fluid and rigid. Thus, we argue that fans engage in an active process of determining who is and is not included in fan cultures through Twitter use.

JWST reveals widespread AGN-driven neutral gas outflows in massive z ~ 2 galaxies

ABSTRACT We use deep JWST/NIRSpec R ∼ 1000 slit spectra of 113 galaxies at $1.7 < z < 3.5$, selected from the mass-complete Blue Jay survey, to investigate the prevalence and typical properties of neutral gas outflows at cosmic noon. We detect excess Na id absorption (beyond the stellar contribution) in 46 per cent of massive galaxies (log M*/M⊙ > 10), with similar incidence rates in star-forming and quenching systems. Half of the absorption profiles are blueshifted by at least 100 km s−1, providing unambiguous evidence for neutral gas outflows. Galaxies with strong Na id absorption are distinguished by enhanced emission line ratios consistent with AGN ionization. We conservatively measure mass outflow rates of 3–100 M⊙ yr−1; comparable to or exceeding ionized gas outflow rates measured for galaxies at similar stellar mass and redshift. The outflows from the quenching systems (log(sSFR)[yr−1] ≲ −10) have mass loading factors of 4–360, and the energy and momentum outflow rates exceed the expected injection rates from supernova explosions, suggesting that these galaxies could possibly be caught in a rapid blowout phase powered by the AGN. Our findings suggest that AGN-driven ejection of cold gas may be a dominant mechanism for fast quenching of star formation at z ∼ 2.

Corundum genesis at the Blue Jay Sapphire occurrence (British Columbia, Canada) as a record of metamorphism and partial melting in the Monashee Complex

Corundum genesis at the Blue Jay Sapphire occurrence (British Columbia, Canada) as a record of metamorphism and partial melting in the Monashee Complex

The Bold News of Birdcalls by Edward Morin

Reviewed by: The Bold News of Birdcalls by Edward Morin Meg Kearney (bio) the bold news of birdcalls Edward Morin Kelsay Books https://kelsaybooks.com/products/the-bold-news-of-birdcalls 102 pages; Print, $18.50 "It might almost be said that the birds are all birds of the poets and of no one else, because it is only the poetical temperament that fully responds to them," said John Burroughs in the opening line of his Birds and Poets (1877). As proof, the world abounds with poems about and inspired by birds. Although Edward Morin's new book often strays from that feathered subject, The Bold News of Birdcalls is filled with a variety of songs as well as the "news" of stories. The collection is divided into four sections of fairly equal size, each with a varied tone suggested by its title: "Noise of Blue Jays," "Melody of Wrens," "Endurance of Robins," and "Passage of Swans." With boisterous, troublesome jays ("sinister as Dutch elm disease") as its [End Page 136] backdrop, part 1 explores themes of life and death through its free-verse elegies for fellow poet-teacher friends, a poem titled "Icicles" ("Stilettos of ice, / as many as stabbed Caesar"), as well as a gripping narrative detailing the speaker as victim of an armed robbery that nearly saw him killed. A tribute to those "black-winged acrobats," "Bank Swallows" almost reads like a love poem as the speaker recalls finding the swallows' nest: "Remember, love, our barefooted climb / in dry roots thin as hair, up the sliding, / steep sand hill?" But it ends on an ominous note as the birds "flutter and scold above us / … throwing shadows the size of hawks." In "Depression," a jack-o'-lantern sits "ravaged" in the post-Halloween season just as we humans are ravaged by the passing of years; its "limp mouth / twists crookedly as during a stroke." And the last poem in the section, "Yes," tells the story of Joe Sartori, a neighbor of the speaker's parents whom the speaker visits when home from college. Sartori, wheelchair-bound and nearly completely paralyzed, is capable of saying only one word: "Yes." This sort of one-note song proves to be an inspiration to the speaker, when he is old enough to appreciate the affirmation embodied in the word. Part 2 kicks off with a sort of ode in tercets to the "plain-brown-wrappered wren" who appears in April seeking summer "housing." While the goldfinches "emulate forsythias' hue," the plain wren is a "friend of gardeners" with a surprisingly strong song: Voice vibrations pulsate from chin through tall throatand halfway down the chest. Such breath control!What long, loud peals for such a little bell. This is a section of nostalgia, with the speaker recalling memories of a childhood spent in Michigan's Upper Peninsula. We take a ride on the "Milk Train"; we meet Brad, a high school classmate who died young; we hear the clang of metal on glass as carpenter's nails are poured into a jar; we join in the rallying cry to rid the Midwest's wetlands of the invader-phragmites choking out the cattails and pushing out the wildlife; we listen to a fish story of "The Big One" that got away; and wince when a man falls from a ladder as well as when the baseball coach calls a twelve-year-old second baseman an "idiot," only to remember—much to his embarrassment and horror—that the boy is "slow witted." The speaker is haunted by his mistake, recalling being labeled a [End Page 137] "moron" by schoolmates as a youth; and "Now that I'd acted really dumb, the mantra / 'You idiot!' choked deep in my throat." Morin's is a warm and empathetic voice, buoyed and inspired by birds. His very soul is lifted by seeing them and hearing their calls—"as when indigo buntings fly through sunlight, / magically changing from black to bright blue" and when from the canopy of deep woods ringsone distant thrush's haunting descant …This recluse trills its two voice boxeslike Pan's double flute. The poems in part 2 are often written in...

Black Herman and the Rest of Us

Black Herman and the Rest of Us E. Ethelbert Miller (bio) (for Benjamin Rucker, 1889–1934) I can still remember Dr. Stephen Henderson in his small office in Founders Library of Howard University eating a half-smoke at his desk. He had been reading about Toni Morrison. Newsweek magazine had put her on their March 30, 1981, cover and placed the words "Black Magic" near her head. Henderson was munching and mumbling about how white people could only explain Black genius as being something strange and mystical. Was it possible Morrison had a big pot somewhere and simply had to stir and add characters and ingredients to produce a novel? If one possessed a wand, was it necessary to master craft? Black intelligence has always been questioned. History celebrates our bodies and not our minds. Black writers have always had to prove themselves as if they were being forced to stand on a literary slave block. How good can a Black writer mimic a white writer? Can a Black writer master form and master one's craft without a master? All my life I wanted to wear hats like Thelonius Monk or sit down in front of a computer and play the keys like Cecil Taylor. Who would then question my line breaks or my funky sonnets? Who would ask if my work was universal? "Do you only write Black poetry?" This is the equivalent of a Black poet being stopped by the police. The asking of the question is brutal. It's a knee on one's imagination. When Black poets do certain things, people stare. I wonder if people stared at the hem in Gwendolyn Brooks's sonnets as if she were Aretha Franklin singing "Nessun Dorma." During the height of the COVID pandemic I found myself spending more time in my backyard. I became more contemplative and aware of nature. I watched blue jays, cardinals, robins, and squirrels flying and running around the large statue of Buddha that sits in my yard. While doing "quiet" thinking I thought of my brother, Richard, who joined a monastery in 1962. He went off to the Trappist community of the Abbey of the Genesee in Piffard, New York, where the monks made bread. I imagined him stopping for a moment [End Page 108] and taking in his new surroundings. My brother was one of those individuals who was influenced by Thomas Merton. Thinking about the outdoors and my brother inspired me to reread a collection of Merton's writings called When the Trees Say Nothing. This was a small book given to me a few years ago by my friend Joanna Chen, a writer and translator living in Israel. I was particularly moved when I came across these words by Merton: How necessary it is for monks to work in the fields, in the rain, in the sun, in the mud, in the clay, in the wind: these are our spiritual directors and our novice masters. They form our contemplation. They instill us with virtue. They make us as stable as the land we live in. As I sat behind my house I wrote poems. I started writing haiku. As many of us worried about the spreading pandemic and the increasing number of deaths around the world, I became aware of my own mortality. Staring at the Buddha in my yard, I was reminded of the importance of mindfulness, the sacredness that comes with each breath one takes and the celebration of the moment. When I started writing poetry in the late sixties and early seventies, I wrote short poems. I was influenced by Langston Hughes, Norman Jordan, and the early work of Sonia Sanchez and Haki Madhubuti (then Don L. Lee). This soon became an invitation and an opportunity to begin to "go steady" with haiku. I like the simplistic structure and the connection it makes to nature. I like the playfulness in how the language might pause suddenly, the emphasis on an image or a moment in time. My regular writing of haiku soon became a working manuscript—the little book of e. When one thinks of African American poetry and the writing of haiku, one immediately thinks...

Preferences of avian seed-hoarders in advance of potential American chestnut reintroduction

Nut-bearing trees such as oaks (Quercus genus) and American chestnut (Castanea dentata, hereafter: chestnut) rely on scatter-hoarding animals for seed dispersal. With the pursuit of blight-resistant chestnuts for eventual reintroduction into eastern hardwood forests of the United States, it becomes important to understand how foraging preferences of avian seed-hoarders will influence chestnut dispersal in oak-dominated forests. Using six seed selection trials over three years and two “seasons” (early fall and late fall), we assess the relative seed preferences – when gathering seeds for hoarding or consumption – of five species of avian seed dispersers in southeast Ohio. In each trial, we presented an equal number of chestnuts and two species of common acorns, black (Q. velutina) and white oak (Q. alba), to wild birds on feeding platforms monitored by cameras. We used Bayesian discrete choice models to determine preferences of each species, and estimate the influence of natural variation in background mast availability (i.e., different years and seasons). Blue Jays (Cyanocitta cristata) showed a consistent preference for the seeds of black oak over chestnut over white oak, and the strength of preference for black oak increased in late season when acorns were scarce. Other species showed variable preferences, with White-breasted Nuthatch (Sitta carolinensis) the only species to prefer chestnuts over both acorns, though sample size was small (n = 26 selections). Our results suggest chestnuts are used by a host of avian seed-hoarders that may facilitate dispersal of chestnut, particularly in years of black oak mast failure.

Disappearances

Disappearances Karin Lin-Greenberg (bio) i Every afternoon, my landlord, who owns the duplex we both live in, throws birdseed and unshelled peanuts off her back deck onto the lawn below. Moments later, birds appear. Some days there are blue jays. Some days there are sparrows. Some days there are mourning doves. And some days there are northern flickers, woodpeckers who, strangely, peck at the ground with their sharp beaks. Northern flickers usually eat ants and beetles dug from the earth, but perhaps they, like many of the animals who frequent the large, grassy backyard, can't resist the buffet of seeds and nuts. When I peer out the window, it looks as if the backyard is being overtaken by flocks of birds. Yet scientists say birds are disappearing. They say there are three billion fewer birds in North America than there were in 1970. The birds who've been disappearing—a euphemism, of course, for dying off—are common, ordinary, the kinds of birds that appear in the backyard to peck at my landlord's offerings. Because many species of birds seem so prevalent, people don't even realize the birds are disappearing; they don't realize there's a crisis at hand. After all, how often do we even notice what's not there? ii Several years ago, one of my English Department colleagues passed away. I can't honestly say we were friends, but perhaps we could have been if we'd had more time together. Some afternoons, during my office hours, she'd stop by my office and sit in one of the red chairs my students sit in during conferences. We'd talk for a while about ordinary things, like our pets or what we did over the weekend. I've always been nervous about stopping into other people's offices, worried I'm disturbing their work, so I rarely do. But I was always glad when my colleague came in and spent some time talking with me. [End Page 36] Now, there is always a reminder of her when I'm at work. When I press the scanner function on the copy machine in the faculty lounge, a grid of small boxes with last names in each box appears on the screen. Press one of the boxes, and the scanned material is sent to that person's e-mail inbox. The square with my name is next to the square with my colleague's name. No one has removed her name, even three years after her death, so every time I scan stories and essays and poems I see her name. Some nights, when I'm at work late and am the only one remaining on the hallway, I go to scan something for the next day's classes and see her last name next to mine and feel a small wave of sadness. Often, when I stand by the photocopier, the lights in the lounge—controlled by motion sensors—shut off, and I'm plunged into darkness. I stand still in the shadowy room, the only sound the copier churning, and think how a photocopier in a dark room is such a strange site of remembrance. iii Before my landlord started feeding the birds in the backyard, she fed other animals in our front yard. During the day, she put piles of cut-up apples on the lawn, and deer and wild turkeys came. Each night, she threw hot dogs and fluffy white buns onto the front lawn, and gray foxes and raccoons appeared. Often, my husband and I looked out an upstairs window and watched the animals below, lit by the dim porch lights. They ate the hot dogs and buns, a meal I could not help but think was so far removed from food actually found in nature. Sometimes the raccoons would hiss and threaten other raccoons, but the raccoons and foxes ignored each other, contentedly chewing like diners in a restaurant, strangers seated at adjacent tables. Then the baby raccoons, the kits, arrived. They were balls of fluff with tiny feet. The two kits would follow their mother toward the duplex, grab food in their jaws, and then, with pieces...

Halo: A Corona Pastoral

Halo: A Corona Pastoral Steven Leyva (bio) 1. The accordion of icicles has paused its torch songand the snow-blind cardinal sings the red from its back into the dawn’s plaintive daylight, which rubs a thumb acrossthe sagging gutters of row homes and alleys without consideringa single lily. What is cruel here? No favor given to the green hillsscratching the belly of Cumberland, MD. Abandoned mills kick in their sleep like dreaming dogs. No meritocracycan save Ellicott City from another flood. The Orioles’off-season has all of Baltimore in a beer glass. Does anyone rememberthe name of the last mayor sent to jail? At the car wash down the block, graffiti separates one water from another. O Godof the voided year, of the indifferent sunlight, give usthe daily bread of quarantine: the longing to be touchedby a letter in the mail, the bald cry in the bathroom, the music of snow. [End Page 8] 2. By a letter in the mail, the bald cry in the bathroom, the music of snow,love has learned its last arpeggio. What good is it to singin the empty amphitheater of winter? And yet the sparrow drags the diva of spring back again. Encore after encore. The blue jays evicting the otherbirds from a hollowed-out gourd, the inconsistent applause of cookwarecoaxed from the back of a cabinet, the exhaust fan whistling a round. Love is a chord we cannot pluck out of morning air. Not alone. Every instrumentmust be touched, held aloft on the crown of a shoulder, kissed, or left mute.Old tabula rasas of bay windows manifest our breath, asking, Won’t youwrite your name? Anything to be touched. The chime of notifications no one confuses for a love song, but notice the sincere chorus of crocusaccompanying the crepe myrtle in the yard, and the stubborn rosemarybullying the garden, and the scrape of the postal truck weighed with late mail,all these altars burning in our eyes. Look at how much we don’t know about loneliness. [End Page 9] 3. All these altars burning in our eyes. Look at how much. We don’t know about lonelinesssought. Cities no longer coughing on suvs. Let me clear my throat. The ringletof lampposts on Main Street as useless as a rosebush in winter. The Sold Out signshanging on the grocery shelves. Give me a break. The land makes a hymnwithout lyrics. No sense in mumbling. Shenandoah sung like a ghost of hallelujahin the praise the Potomac negotiates. Every kind of hum arrives on the bonesof derelict bridges below Harper’s Ferry. Rust by any other name. The dead stars hang like a DJ’s poster saying Coming Soon. And the turntablesof sun and moon scratch the sky’s vinyl. How can we not dancein the kitchen alone, making toast, frying an egg? Every day we are searchingfor the perfect outfit, a few fly boots, a coat that won’t quit, to enter the clubof memory, slipping the bouncer a 20-dollar bill from our childhood. The petty cashbegged at a parent’s knee. Anticipation. The fear of walking home empty- handedafter asking for a lover’s number. The deft touch of a porch light across the cheek. [End Page 10] 4. After asking for a lover’s number, the deft touch of a porch light across the cheekis like horizon’s blushing grin in the daily aubade of dawn. Amen. After asking for a lover’s number, the deft touch of a porch light across the cheekis like the anglerfish, whose luminosity and ugliness coexist. Amen.After asking for a lover, number the deft touches of a porch light across the cheek.Is there enough to fill the wolf ’s mouth and see what it eats? Amen,after asking for a lover’s number. The deft touch. A porch light across the cheekis like any other kiss. Tender but never enough. Shameless. Amen.After asking for a lover, number each deft touch. A porch lights. Across a cheek-bone...

Overview introduction for educational programme "Blue Jay programme", and introduction of "Origami engineering" for deployable structures

The "Blue Jay Programme" is an educational program for students (mainly university students and technical college students) from educational institutions around the world that utilizes our large scale balloon launch method. This programme will be from the designing the satellite, the students work together with our engineers to design, build, and verification / test the manufactured satellite on the ground, and finally launch the manufactured satelite to the stratosphere using our launch method and verify the final satellite in the stratosphere.

Responses of Female Yellow Warblers to Playbacks Signaling Brood Parasitism or Predation Risk: A Quasi-Replication Study

Many avian species are negatively impacted by obligate avian brood parasites, which lay their eggs in the nests of host species. The yellow warbler (Setophaga petechia), which is host to the brood-parasitic brown-headed cowbird (Molothrus ater), represents one of the best-replicated study systems assessing antiparasitic host defenses. Over 15 prior studies on yellow warblers have used model-presentation experiments, whereby breeding hosts are exposed to models of brown-headed cowbirds or other nest threats, to test for anti-parasitic defenses unique to this species. Here we present results from our own quasi-replication study of the yellow warbler/brown-headed cowbird system, which used a novel design compared to previous experiments by pivoting to conduct acoustic playback treatments only, rather than presenting visual models with or without calls. We exposed active yellow warbler nests to playbacks of brown-headed cowbird chatters (brood parasite), blue jay (Cyanocitta cristata; nest predator) calls, conspecific “seet” calls (a referential alarm call for brood parasitism risk), conspecific “chip” calls (a generic alarm call), or control wood thrush (Hylocichla mustelina; harmless heterospecific) songs during the incubation stage. Similar to previous studies, we found that female yellow warblers seet called more frequently in response to playbacks of both brood parasitic chatter calls and conspecific seet calls whereas they produced more chip calls in response to the playback of nest predator calls. In contrast, female yellow warblers approached all playbacks to similar distances, which was different from the proximity patterns seen in previous studies. Our study demonstrates the importance of both replicating, and also pivoting, experimental studies on nest defense behaviors, as differences in experimental design can elicit novel behavioral response patterns in the same species.

Eastern Wood-Pewee (Contopus virens) reproductive success in red pine plantations and deciduous forests in Ontario, Canada

Pine plantations comprise about 7% of total world forest cover and are increasing across the globe. We compared settlement times, breeding densities, and the effects of time, habitat, and nest-site characteristics on the nest success of Eastern Wood-Pewees (Contopus virens) in red pine (Pinus resinosa) plantations and deciduous forest stands in south-central Ontario, Canada, in 2007 and 2008. Our goal was to evaluate the quality of these 2 habitats for this declining aerial insectivore. Pine plantations and deciduous forest stands were settled nearly simultaneously and at similar breeding densities, suggesting no preference for either habitat. Nest success in pine plantations (22%) was lower than in deciduous forests (35%), corresponding to higher counts of red squirrels (Tamiasciurus hudsonicus) and Blue Jays (Cyanocitta cristata) in plantations. Daily nest survival was lowest when nestlings were about 5 d old, but improved substantially as nestlings aged, and over the nesting season. In both habitats, increased nest visibility was correlated with decreased nest survival. In pine plantations, nest survival was higher where trees were more dispersed, while in deciduous forests, nests situated farther from tree trunks had higher survival rates. In both habitats, Eastern Wood-Pewees may use outward branches, when available, to detect movement and then evade potential nest predators. Although pine plantations provide breeding habitat for Eastern Wood-Pewees, management that increases hardwood understories and overstories may help to reduce visibility of Eastern Wood-Pewee nests and to reduce the populations of generalist songbird predators.

Does the intrusion of an avian nest predator elicit a change in the behaviour of a canopy-nesting passerine?

Abstract Many studies have shown that nest predators affect their prey indirectly by inducing changes in the behaviour of the prey. Studies suggest that the type and degree of nest defence strategies depends heavily on species, along with nest type and location. One such strategy, nest vigilance, allows individuals to collect information and make informed decisions based on their surroundings. In this study, we simulated the intrusion of a common avian nest predator (blue jay, Cyanocitta cristata) into the territory of nesting cerulean warblers (Setophaga cerulea) and evaluated eight different behavioural variables to determine their response to the nest predator. Female cerulean warblers were more vigilant on their nest when exposed to a potential predator compared to a nest with lower threat of predation. Females exposed to a nest predator increased incubation bout by 109% and brooding bout by 60%. Our data also suggest that male cerulean warblers reduce their provisioning rate during the early nestling stage (−1 feeding/hour) and late nestling stage (−3 feedings/hour), although more data are needed. Modification of incubation bout length and nestling provisioning rate are common strategies employed by songbirds to reduce activity around the nest, by decreasing detection opportunities of visually-oriented nest predators. Currently, the only understanding we have on how cerulean warblers respond to a nest predator is based on observational data. The results of this study provide the first evidence that cerulean warblers are able to identify species that pose a threat to the safety of their nest, and that they modify their behaviour to reduce nest detection by predators. The results of this study provide a better understanding of a relatively unknown aspect of the breeding behaviour of this species. This study is also first to describe how an open-cup, canopy-nesting species responds to an increase in nest predation threat.

Pairing status moderates both the production of and responses to anti‐parasitic referential alarm calls in male yellow warblers

AbstractDefending offspring incurs temporal and energetic costs and can be dangerous for the parents. Accordingly, the intensity of this costly behavior should reflect the perceived risk to the reproductive output. When facing costly brood parasitism by brown‐headed cowbirds (Molothrus ater), where cowbirds lay eggs in heterospecific nests and cause the hosts to care for their young, yellow warblers (Setophaga petechia) use referential “seet” calls to warn their mates of the parasitic danger. Yellow warblers of both sexes produce this call only in response to cowbirds or seet‐calling conspecifics. Seet calls are mainly produced during the laying and incubation stages of breeding, when risk of brood parasitism is highest, rather than during the nestling stage. On the other hand, general alarm calls (chips) are produced throughout the nesting cycle and are also used in conspecific interactions unrelated to nesting. We hypothesized that context shapes responses prior to breeding as well, such that yellow warblers without a mate and active nest would be less likely to respond to playbacks that simulate brood parasitism risk. To test this hypothesis, we presented playbacks of two nest threats, cowbirds (brood parasite) and blue jays (Cyanocitta cristata; nest predator), on territories of unmated male warblers (unpaired) and male warblers with a known mate (paired). We found that unpaired males were unresponsive toward playbacks indicating nest threats, whereas paired males were significantly more aggressive and vocal toward these playbacks compared to control playbacks. However, both paired and unpaired males were vocally responsive toward chip calls, which are informative for males regardless of pairing status. Male yellow warblers appear to adjust their responses during the earliest stages of breeding depending on the contextual relevance of specific threat stimuli, and together with prior studies, our work further supports that referential seet calls are associated with stage‐specific risk of brood parasitism.

One Nation, Two Teams: Repositioning the Toronto Blue Jays Among the Threat of a New Entrant

While many teams face difficult decisions regarding their branding, this case emphasizes how external factors can dictate marketing strategies. The Montreal Expos returning to Major League Baseball poses many threats and opportunities for the Toronto Blue Jays. As a result, the Blue Jays must reconsider their use of national identity in their branding—and whether it is appropriate to transition from being Canada’s only team to now sharing the market with the Expos. Nevertheless, the Expos’ return to Major League Baseball provides the Blue Jays with an opportunity to explore new marketing strategies. Case participants are tasked with repositioning the Blue Jays’ marketing strategy in response to the Expos’ return.

Baseball, Blue Jays, Bracelets, and Barbed Wire: Picture Books and the Visual Iconography of Japanese American Incarceration

Baseball, Blue Jays, Bracelets, and Barbed Wire: Picture Books and the Visual Iconography of Japanese American Incarceration