Journal Club: Starlings on Prozac: How pharmaceuticals may affect wildlife

SUMMARY: Recent research suggests that the commonly prescribed psychiatric drug, Prozac, occurs at environmentally relevant concentrations that can significantly alter behaviour and physiology in wild birds

Adult common starling, Sturnus vulgaris. Image: Tim Felce (Airwolfhound)

Adult common starling, Sturnus vulgaris. Image: Tim Felce (Airwolfhound)

A study recently published in the peer-reviewed journal, Current Biology, revealed that some psychiatric pharmaceuticals commonly used to treat depression and Parkinson’s disease significantly alter human behaviour (doi:10.1016/j.cub.2015.05.021). In that report, the authors found that just one dose of a serotonin-enhancing drug increased the likelihood that healthy volunteers were more protective of themselves and others, whereas a dopamine-enhancing drug made healthy people more selfish.

Clarifiers are widely used for wastewater treatment.

Clarifiers are widely used for wastewater treatment.

Many pharmaceuticals are only partially metabolised by the body into other compounds, some of which are still active. Although some of these metabolites remain in certain tissues, others are excreted and end up in wastewater treatment plants. Sewage treatment works cannot deactivate or remove all of these myriad compounds from water, nor from the sewage sludge that is used to fertilise farmed fields. Some of these pollutants are then taken up by invertebrates, which then are consumed by birds, bats and other wildlife. Thus, treated water and sewage sludge are typical vehicles whereby pharmaceutical contaminants enter the environment, where humans and wildlife encounter them.

Poo or pee: is that the end of the pharmaceutical story?

This, then, raises the question: how do psychiatric pharmaceuticals and their metabolites affect wildlife after they are excreted into the environment? This is an important line of inquiry because pharmaceuticals, which are specifically designed to alter human physiology and behaviour at low concentrations, can also affect other vertebrates. For example, it has recently been found that nestling wild starlings, Sturnus vulgaris, grow more slowly and show poorer immune response than controls when fed endocrine-disrupting chemicals, including 17α-ethinylestradiol, a common ingredient of the contraceptive pill (doi:10.1111/j.1365-2664.2010.01931.x). But so far, studies of the effects upon wildlife of environmentally relevant concentrations of pharmaceuticals are rare, particularly for terrestrial species and exposure routes.

researchbloggingLogo This inspired Kate Arnold, a Royal Society University Research Fellow in the environment department at the University of York, to investigate the effects of the commonly prescribed psychiatric pharmaceutical, fluoxetine (Prozac), upon wild starlings. In the environment, this antidepressant and its metabolites originate from human waste and are present in surface water at concentrations as high as the µg l-1 level. (For reference, the therapeutic dose of fluoxetine is 20 to 60 mg orally per day for an adult.)

Together with her colleagues, Dr Arnold captured 24 wild starlings, fitted them with transponder tags, separated them into two treatment groups and housed them in outdoor aviaries. Five days each week, birds in the experimental group were fed wax worms that had been injected with fluoxetine at concentrations that simulated what the birds would be exposed to by feeding on invertebrates at a wastewater treatment plant (0.92 µg d-1). Control birds were fed wax worms without fluoxetine.

The birds’ feeding behaviours were then monitored using electronic tag readers as they visited food trays throughout the day. These electronic tag readers allowed the researchers to identify changes in the birds’ foraging behaviours throughout the day (figure 1):

Figure 1. Mean (+/- 1 s.e.) feeder visits per hour per bird for the first and last 4 h of data against time for control (blue diamonds) and fluoxetine-treated birds (red squares). Time is expressed relative to sunrise ( a) and sunset ( b) and so the 4 h period for which observations were taken depended upon the time when birds first fed in the morning and last fed at night.

Figure 1. Mean (+/- 1 s.e.) feeder visits per hour per bird for the first and last 4 h of data against time for control (blue diamonds) and fluoxetine-treated birds (red squares). Time is expressed relative to sunrise (a) and sunset (b) and so the 4 h period for which observations were taken depended upon the time when birds first fed in the morning and last fed at night.

Birds in the treatment group showed conspicuous changes in foraging behaviour from controls.

“The normal way that birds forage during winter is when they’re hungry, they have a big breakfast and then during the day they forage to meet their energetic requirements”, said Dr Arnold in a video interview.

“Then before bedtime, it has a hearty supper and then it can survive a cold dark winter’s night. And that’s what our control birds did, as we expected.”

“But birds that had been exposed to environmentally-relevant concentrations of fluoxetine, they didn’t do that. They essentially snacked throughout the day and didn’t have a hearty breakfast, so their foraging routine was completely changed”, said Dr Arnold.

This seemingly minor change in behaviour can affect these birds’ survival in the wild. For example, birds can dramatically change their body mass in a short period of time to ensure that they have enough fat reserves to provide sufficient insulation and energy to survive periods without food. Dr Arnold went on to explain that birds that eat too much during the day are too heavy to escape predators.

Why care about wild starlings on Prozac?

Fluoxetine is not the only pharmaceutical, nor is it the only antidepressant, that is present in the environment at detectable levels. Further, this gallimaufry of environmental pharmaceuticals and their active metabolites interact with each other in unknown ways, potentially creating a dangerous brew that is more potent than any individual contaminant due to additive or synergistic interactions. These interactions could lead to powerful or detrimental effects in wildlife — and indeed, in humans, too.

For these reasons, it is important that additional research be done to determine the identity and extent to which pharmaceuticals accumulate in the tissues of animals, how those animals fit into the food chain and how this bioaccumulation can impact behaviour and overall health in wildlife and people.

Sources:

Tom G. Bean, Alistair B. A. Boxall, Julie Lane, Katherine A. Herborn, Stéphane Pietravalle and Kathryn E. Arnold (2014). Behavioural and physiological responses of birds to environmentally relevant concentrations of an antidepressant, Philosophical Transactions of the Royal Society B: Biological Sciences, 369 (1656) 20130575-20130575. doi:10.1098/rstb.2013.0575 [₤]

Also cited:

Molly J. Crockett, Jenifer Z. Siegel, Zeb Kurth-Nelson, Olga T. Ousdal, Giles Story, Carolyn Frieband, Johanna M. Grosse-Rueskamp, Peter Dayan, Raymond J. Dolan (2015). Dissociable Effects of Serotonin and Dopamine on the Valuation of Harm in Moral Decision Making, Current Biology, published online ahead of print on 2 July 2015. doi:10.1016/j.cub.2015.05.021 (OA)

Shai Markman, Carsten T. Müller, David Pascoe, Alistair Dawson, Katherine L. Buchanan (2011). Pollutants affect development in nestling starlings, Sturnus vulgaris, Journal of Applied Ecology, 48 (2), 391–397. doi:10.1111/j.1365-2664.2010.01931.x (OA)

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Grrlscientist can be found on on her eponymous Guardian blog, and she’s quite active on twitter: @GrrlScientist.

Posted in Birds, Environment, Journal Club | Tagged , , , , , , , ,

Journal Club: Birds identify good nuts by listening to them

SUMMARY: Wild birds identify “good” seeds without first opening the shells by weighing them and by listening to the sound produced when clicking their beaks on the shell, according to a recent study

An adult Mexican jay, Aphelocoma wollweberi. Credit: Alan Vernon, CC BY 2.0

An adult Mexican jay, Aphelocoma wollweberi. Credit: Alan Vernon, CC BY 2.0

A previous study suggested that birds prefer seeds or nuts that are heavier or denser (Heinrich et al, 1997), but there has been very little research in the ensuing twenty years into which sensory cues are used by birds to make these important decisions.

researchbloggingLogo To investigate, an international team of scientists from South Korea and Poland conducted field studies with Mexican jays, Aphelocoma wollweberi, to better understand how these food-caching birds identify nutritious seeds without first opening the shells to inspect the contents.

Mexican jays are largish songbirds that have a long blue tail, blue wings and head, a blue-grey mantle, a pale grey breast and underparts. Mexican jays are cooperative breeders where several subadults help tend the nestlings produced by the dominant pair in the group. Most of these helpers are offspring of the dominant pair from earlier years, but unrelated individuals will also join a group and help raise the young. Although Mexican jays are omnivorous, they do cache acorns and nuts throughout the late summer and autumn that serve as their primary food during the winter.

The research team studied nine such groups of Mexican jays living on the arid eastern slopes of the Chiricahua Mountains in Arizona. These birds are individually colour-banded and have been trained to approach their own particular feeding arena in response to the sound of a police whistle. Sunflower seeds, acorns and peanuts are provided at each feeding arena that the birds can carry away and cache nearby.

A Mexican jay, Aphelocoma wollweberi, appears to evaluate the content of a peanut by weighing it in its beak and by listening to the sound created when clicking its beak on the pod. (doi:10.1007/s10336-015-1193-6) Credit: Maciej Fuszara

A Mexican jay, Aphelocoma wollweberi, appears to evaluate the content of a peanut by weighing it in its beak and by listening to the sound created when clicking its beak on the pod. (doi:10.1007/s10336-015-1193-6) Credit: Maciej Fuszara

Three experiments tested how the birds evaluated peanuts

The team designed three tests that were repeated hundreds times (using tens of thousands of peanuts) in 2008, 2009 and 2012 in the nine jay groups, to evaluate the sorts of information that the birds might be learning by handling peanuts.

First, the team tested whether the birds could identify if similarly-sized peanuts contained nutmeats simply by looking at them. To do this, they gave the jays 20 similarly-sized peanuts, ten of which had been emptied of nutmeats and the pods superglued closed, whilst the other ten had been opened, the nutmeats glued to the pod interior to prevent rattling, and their pods superglued closed. In this experiment, the “normal” peanuts were 4 times heavier than the empty peanuts.

Second, the team tested whether the jays could distinguish between similarly-sized peanuts with a normal mass or with a slightly heavier mass than normal. To do this, they provided the birds with 20 similarly-sized peanuts that had been weighed. Ten of these peanuts were of “normal” mass and had been opened, the nutmeats glued to the pod interior and superglued closed, and ten peanuts were 1.6 times (1 gram) heavier than “normal”. The heavy peanuts were prepared by putting non-toxic clay inside each pod before they were superglued closed.

Third, the team tested whether the jays chose peanuts visually based solely on size. They provided the jays with 20 peanuts, ten of which were small, containing only a single nutmeat, and ten of which were large, containing three nutmeats. As before, the team opened each peanut, glued the nutmeat to the pod interior and superglued the pods closed. But before resealing the pods of the “triple” peanuts, they removed two of the three nutmeats so all peanuts, regardless of size, had similar masses.

Slow motion videos revealed how the birds handled peanuts

The team filmed the jays with a portable high-speed camera (250 frames per second, and occasionally 500 or 1000 fps) to capture minuscule details of how the birds handled peanuts. The team later analysed the films to identify whether (and by how much) the birds opened and closed their beaks when handling a peanut, and estimated the velocity of the beak when it closed on the peanut pod.

The videos revealed that the jays evaluated each peanut whilst handling it by using very fast beak and head movements. In the first and second experiments, the birds consistently chose heavier peanuts. When provided peanuts that were obviously different in size, as in the third experiment, the jays handled the larger peanuts before rejecting them and choosing the smaller peanuts.

“The jays figured out that the larger pods did not weigh as much as they should and the birds preferred the smaller pods, which weighed as expected for their size”, said the study’s co-author Elzbieta Fuszara, a biologist at the University of Warsaw, in a press release. She noted that, basically, the birds behaved as if they knew that “something is wrong” with the larger nuts.

Birds listen to sounds created by clicking their beaks on a peanut

Preliminary analyses of the data suggest an alternative explanation for how the jays decided which peanut to cache.

“Although the peanuts in our experiments had similar mass and look, they produce different sounds during handling”, write the authors in their paper. Further, despite gluing the nutmeats inside the pods to prevent them rattling, the birds created sounds by rapidly clicking their beaks on the peanuts.

“If heavy/full peanuts have consistently different auditory features than light/empty ones, then the Jays would also reject the artificially lighter triple peanuts, if they follow only the auditory cues without any cognitive processes about the match between weight and visual size.”

In short, birds choose the best seeds and nuts to store away for a snowy day by using the same sensory cues used by melon-thumping humans in a supermarket.

Source:

Piotr G. Jablonski, Sang-im Lee, Elzbieta Fuszara, Maciej Fuszara, Choongwon Jeong, Won Young Lee. (2015). Proximate mechanisms of detecting nut properties in a wild population of Mexican Jays (Aphelocoma ultramarina), Journal of Ornithology, published online in advance of print; doi:10.1007/s10336-015-1193-6 [₤]

Also cited:

Bernd Heinrich, Chris C Joerg, Sean S Madden, Emory W Sanders (1997). Black-capped Chickadees and Red-breasted Nuthatches “Weigh” Sunflower Seeds, The Auk, 114(2):298-299 [Open Access PDF]

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This piece has been edited and reformatted from the original.

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Grrlscientist can be found on on her eponymous Guardian blog, and she’s quite active on twitter: @GrrlScientist.

Posted in Behavior, Birds, Evolution, Journal Club | Tagged ,

Birth of the blue morphos

SUMMARY: Today’s “Museum Monday” features a visit to the Natural History Museum’s new Sensational Butterflies exhibition, where we watch a time-lapse video of their blue morpho butterflies emerging from chrysalises

Adult peleides blue morpho, Morpho peleides, wings open. (Also known as the common morpho, or as The Emperor.) Credit: Thomas Bresson (CC BY 3.0)

Adult peleides blue morpho, Morpho peleides, wings open. (Also known as the common morpho, or as The Emperor.) Credit: Thomas Bresson (CC BY 3.0)

The Natural History Museum’s filmmakers recently captured a time-lapse video of the first of their blue morpho butterflies emerging from their chrysalises. These butterflies are now on view in their “Sensational Butterflies” exhibition.

Several species of butterflies are commonly known as “blue morphos” so the specific (species) name often precedes the common name: the Sensational Butterflies exhibition’s blue morphos are peleides blue morphos, Morpho peleides.

Blue morpho butterflies are native to Mexico, Central American and the northern regions of South America. In the wild, as they fly through the thick foliage, their wings provide brief flashes of brilliant blue that are visible from a long distance. This helps them find mates and defend their territories.

The blue morpho lives for only 115 days — and most of their lifetime is spent on “the Three Fs”: feeding, flying and … reproduction. As fuzzy caterpillars, blue morphos are nocturnal and herbivorous; munching their way through the leaves from many tropical plant species by night — or they can be cannibals; munching their way through their siblings!

Adult blue morphos lack chewing mouthparts, but instead, they have a long thin hollow tongue, known as a proboscis, that they use as a drinking straw to suck up juices of fermenting fruits, tree sap, and fluids of decomposing animals, fungi, and wet mud. Blue morphos find their food by tasting the air with their club-tipped antennae, and they also can taste with their legs and feet.

The most spectacular feature of butterflies are their wings — all butterflies have four wings — two forewings and two hindwings. Most butterflies’ wings are covered with microscopic scales that provide the colours and patterns — one colour per scale.

Credit: Greg Hume (CC BY-SA 3.0). Adult peleides blue morpho, Morpho peleides, wings closed (Krohn Conservatory in Cincinnati, Ohio).

Credit: Greg Hume (CC BY-SA 3.0). Adult peleides blue morpho, Morpho peleides, wings closed (Krohn Conservatory in Cincinnati, Ohio).

Blue morphos are amongst the largest butterflies in the world, with a wingspan that ranges from 7.5–20 cm (3.0–7.9 inches). The underside of their wings are pigmented with black, brown, tan, orange and white, and with a number of eyespots (ocelli). This colouring provides cryptic camouflage to protect them from sharp-eyed predators, especially at night when the adults roost in the foliage to sleep.

The uppersides of the blue morpho’s wings are vivid metallic blue, edged with black. The blue colouring is not supplied by pigments, but by iridescence, where the scales are arranged in a tetrahedral (diamond) pattern across the wing surface, and where individual scales are comprised of several layers, or lamellae, that reflect incident light repeatedly from each successive layer. This reflected light creates interference that produces wavelengths in the green-blue-violet range (450-550 nm), depending upon the angle at which the wings are viewed (doi:10.1098/rspb.1999.0794).

Blue morphos are threatened by deforestation and by habitat fragmentation. Thanks to their spectacular wings, humans also directly threaten blue morphos by hunting them down for display. But morphos and the other butterflies used in butterfly exhibits throughout the world are raised commercially by indigenous peoples, which gives them an economic incentive to protect their rainforests.

It takes a butterfly or moth only a couple minutes to emerge from its chrysalis, a few more minutes to unfurl its wings by filling them with body fluids, and then several hours for its wings to dry and harden so it can then fly. In today’s “Museum Monday” time-lapse video, we watch two hours of blue morpho emergence distilled down to a mere 47 seconds.

The Natural History Museum’s Sensational Butterflies exhibition is now open and runs through 13 September. You can find the Natural History Museum on twitter @NHM_London

Additional reading:

Vukusic P., C. R. Lawrence & R. J. Wootton (1999). Quantified interference and diffraction in single Morpho butterfly scales, Proceedings of the Royal Society B: Biological Sciences, 266 (1427) 1403-1411. doi:10.1098/rspb.1999.0794 [₤]

Read more about a similar phenomenon to blue morpho wing colouring; the physics of blue colouring and iridescence in bird feathers.

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Grrlscientist can be found on on her eponymous Guardian blog, and she’s quite active on twitter: @GrrlScientist. She sometimes lurks on social media; facebook, G+, LinkedIn, Pinterest.

Posted in Animalia | Tagged , , , , ,

Journal Club: Birdfeeding favours non-native bird species

SUMMARY: Feeding urban birds on bread and seed encourages high densities of introduced bird species at the expense of native species, thereby altering bird communities in cities, according to a new study

Male house sparrow, Passer domesticus. This bird is an invasive species that has been introduced throughout much of the world, where it is dependent upon the presence of humans. Image: Josie Galbraith.

Male house sparrow, Passer domesticus. This bird is an invasive species that has been introduced throughout much of the world, where it is dependent upon the presence of humans. Image: Josie Galbraith.

researchbloggingLogoFeeding wild birds is a hugely popular pastime worldwide. But this is essentially a massive global supplementary feeding experiment with ecological effects that are poorly understood. A newly-published study of bird feeding in New Zealand reports that the common practice of feeding bread and seed alters the species composition observed in urban bird communities such that introduced bird species were the big winners at the expense of native birds. The study suggests that supplementary feeding of bread and seed encourages higher densities of introduced bird species, which may in turn, decrease local populations of native bird species.

Credit: Josie Galbraith. Figure 1. Map of northern Auckland, New Zealand, showing the location of properties participating in an experimental bird feeding study. The urban–rural boundary is also shown, with land zoned as urban shaded in grey. Reference coordinates are expressed as latitude and longitude (WGS84). (doi: 10.1073/pnas.1501489112)

Credit: Josie Galbraith. Figure 1. Map of northern Auckland, New Zealand, showing the location of properties participating in an experimental bird feeding study. The urban–rural boundary is also shown, with land zoned as urban shaded in grey. Reference coordinates are expressed as latitude and longitude (WGS84). (doi: 10.1073/pnas.1501489112)

Bird feeding is certainly one of the most universally popular hobbies in the world. For example, according to a 2006 US Fish and Wildlife Report: “Over 55 million Americans over the age of 16 feed wild birds and spend more than $3 billion a year on bird food, and $800 million a year on bird feeders, bird baths, bird houses and other bird feeding accessories.” In a 2002 report, the Department of the Environment, Food and Rural Affairs (DEFRA) estimated that more than 60 percent of UK households with a garden feed wild birds, and a British Trust for Ornithology (BTO) study analysed data collected during the winter of 2002-2003 by the Garden Bird Feeding Survey, a citizen science project, and reports that 60,000 tonnes of food are presented annually to birds (Glue, 2006).

Considering its tremendous popularity with the public, it might surprise you to learn that feeding wild birds is controversial, particularly amongst ecologists and birders. Much of this controversy is based on assumptions and handwaving since very few scientific investigations into this practice have been published. Basically, the only thing that most scientists can be sure of is that the global scale of bird feeding probably does affect wild bird populations, but no one knows precisely what those effects might be.

A team of scientists from New Zealand and Australia, led by Josie Galbraith, a doctoral candidate in the School of Biological Sciences at the University of Auckland, wanted to know if bird feeding might increase the capacity of urban areas to support birds, thereby enhancing the overall biodiversity of cities. Considering the dietary divide between native and introduced birds living in urban New Zealand, the team predicted that the typical grain-based feeding practices followed the public would increase densities of introduced species at the expense of the more specialised native species.

How do typical bird feeding practices affect native vs. introduced species?

To address this question, the team surveyed wild birds that visited bird feeders placed in the gardens of 23 urban homes in northern Auckland. Eleven of the 23 homeowners provided bird food whilst the other 12 other sites provided no bird food. Every morning during the 18 month study period, homeowners fed birds the two most common foods items offered by New Zealanders who feed birds; pieces of bread and “budgie seed mix”.

Figure 2: Spotted doves, Streptopelia chinensis, and house sparrows, Passer domesticus, crowding together at an experimental feeding station. These species are invasive and are not native to New Zealand. Photograph: Josie Galbraith.

Figure 2: Spotted doves, Streptopelia chinensis, and house sparrows, Passer domesticus, crowding together at an experimental feeding station. These species are invasive and are not native to New Zealand. Photograph: Josie Galbraith.

During this time, 597 surveys (10-minute point counts) were conducted where all birds that were either seen or heard were recorded. A total of 18,228 birds of 33 species were recorded; 16 of which were native species and 17 were introduced. The most commonly observed birds were house sparrows (Passer domesticus; 96.6% of surveys), Eurasian blackbirds (Turdus merula; 91.1% of surveys), silvereye (Zosterops lateralis; 90.8% of surveys), and common myna (Acridotheres tristis; 87.6% of surveys).

Figure 3. Overall (A) species abundance and (B) relative richness of garden birds recorded during 10-min point counts at urban study properties in northern Auckland, New Zealand, before, during, and after implementation of an experimental feeding regime. Key: introduced feeding (F) properties (solid black line); introduced nonfeeding (NF) properties (solid grey line); native F properties (dashed black line); native NF properties (dashed grey line). Vertical red dashed lines indicate the start and end of the feeding regime. Error bars represent SEM. (doi: 10.1073/pnas.1501489112). Illustration:  Josie Galbraith.

Figure 3. Overall (A) species abundance and (B) relative richness of garden birds recorded during 10-min point counts at urban study properties in northern Auckland, New Zealand, before, during, and after implementation of an experimental feeding regime. Key: introduced feeding (F) properties (solid black line); introduced nonfeeding (NF) properties (solid grey line); native F properties (dashed black line); native NF properties (dashed grey line). Vertical red dashed lines indicate the start and end of the feeding regime. Error bars represent SEM. (doi: 10.1073/pnas.1501489112). Illustration: Josie Galbraith.

The team found that the average number of introduced species (solid lines, figure 3A) per survey was well above that for native species (dashed lines, figure 3A) for all properties for the duration of the study. Although the overall number of species present (figure 3A) for all properties did not change during this time, introduced and native species did react differently to feeding. The abundance of introduced species increased on feeding properties during the study (solid lines, figure 3B).

The largest change in introduced species abundance was documented for house sparrows and spotted doves, Streptopelia chinensis. During experimental feeding, sparrow abundance increased by 2.4 at feeding sites and spotted doves were 3.6 times more abundant. Further, the team found that the abundance of spotted doves increased rapidly within two months of the start of feeding, indicating that good news travels fast amongst this species: nearby doves quickly relocated to the feeding sites.

In contrast, the richness of native bird species increased on nonfeeding properties during the study (black dashed line, figure 3A), whereas native species richness remained unchanged at feeding properties (grey dashed line, figure 3A). The overall abundance of native species remained unchanged for both feeding and nonfeeding properties (dashed lines, figure 3B).

The most worrying finding in this study was the correlation between bird feeding and abundance of the endemic grey warbler, Gerygone igata, at feeding sites. During the 18 month study, the grey warbler’s numbers dropped by more than half.

Adult grey warbler, Gerygone igata. Photograph: Tessa Galbraith (courtesy of Josie Galbraith).

Adult grey warbler, Gerygone igata. Photograph: Tessa Galbraith (courtesy of Josie Galbraith).

Why might grey warbler abundance be so dramatically altered by bird feeding?

“They typically forage on insects in the tree canopy but their ability to forage efficiently may be affected by the disruption of higher densities of other birds at feeding sites”, writes Ms Galbraith.

“There is some evidence their numbers are declining anyway, so this study does add to that concern”, Ms Galbraith added.

The grey warbler was voted New Zealand’s “Bird of the Year” in 2007. Adults of this diminutive songbird species have greyish-brown upperparts, whilst its abdomen, throat and breast are greyish-white with just the faintest hint of yellow. The short tail is white underneath, dark brown on top and has white feather tips that are visible in flight. The bird’s face is pale grey with startlingly brilliant ruby-red eyes.

What happens to local bird communities once feeding stops?

When the study ended, the supplementary bird feeding regime stopped abruptly (figure 3). What then did the birds do?

“The abundance of these feeder-visiting birds decreased very rapidly after we stopped the feeding experiment”, writes Ms Galbraith in email.

This observation raises one of the many questions around which bird feeding controversies swirl: were the “feeder birds” so dependent upon being fed that they starved when alternative food was no longer available?

“This decline was probably from birds redistributing in the surrounding neighbourhood once they worked out there was no more food ‘freebies’ available at our study properties, rather than from birds not surviving once feeding stopped. There’s no evidence that dependence on food provided by people is actually a problem for feeder-visiting birds.”

But there is evidence that feeding birds with bread and seed does have an effect on local native bird species: this study revealed significant changes in the composition of the local urban bird community as a result of feeding. Although this study was conducted at a tiny scale — just 11 households with birdfeeders, compared to an estimated 265,000 households feeding birds in six major New Zealand cities — the team found evidence that five common native garden bird species were negatively affected by the experimental feeding regime, although that effect was temporary.

“In New Zealand we typically have more non-natives than natives in our cities, both in terms of the number of species and overall abundance”, wrote Ms Galbraith in email.

“That’s partly down to diet — many of the non-natives are omnivores or granivores, which is perfect for making use of the resources available in cities”, Ms Galbraith pointed out.

“This work certainly suggests bird-feeding favours introduced birds such as spotted doves over native birds, which mostly eat insects, nectar and fruit,” agreed co-author Margaret Stanley, who is a Senior Lecturer in the Biological Sciences at the University of Auckland. Dr Stanley is one of Ms Galbraith’s dissertation supervisors.

How can people help their local native bird species?

“We aren’t suggesting people stop feeding birds”, wrote Ms Galbraith in email. “But we do need to consider how we might feed in such a way that encourages a diversity of birds, minimises the risks to other natives that don’t visit feeders, and certainly avoid practices that benefit non-native, invasive or pest species.”

Matching the types of seed and other foods that you provide so you specifically attract local native species is important. For example, many insectivorous bird species respond well when live insects or insect larvae are provided. Other bird species will be attracted by fresh cut fruits, berries or nectars, and a variety of native seed-eating birds will show up to dine on their “special seeds”.

“If people do want to feed they should be thinking about what species are coming to the food they put out, and perhaps changing their strategy (e.g. food type or mode of presentation) if they are finding their gardens being taken over by just a few species.”

Many bird feeders are specially designed to attract just the desired species, leaving others — the introduced species, one hopes — to search for food elsewhere. In addition to changing the types of foods provided and the sorts of feeders used, other strategies can help native birds, too.

“There are also other ways of encouraging birds into our gardens, including creating bird-friendly habitat by planting a variety of native flowering and fruiting plants and trees, as well as providing a water source”, Ms Galbraith wrote in email.

“These are good alternatives to putting out food — and they also have other benefits in terms of supporting populations of other types of wildlife, including native invertebrates.”

Other strategies that I’ve used include providing proper nest boxes (with appropriately sized entrance holes and anti-predator devices) that native cavity-nesting species will use, and providing a variety of nest materials.

Like a crowded into watering hole in an arid region of Africa, a birdfeeder attracts many birds that would not ordinarily be found feeding in such close proximity. For this reason, another “birdfeeding controversy” is the very real possibility of increased disease transmission, which is exacerbated when the person supplying food does not practice good “birdfeeder hygiene”. Basically, this amounts to washing the bird feeder and all feeding tools with soap or bleach and allowing everything to dry thoroughly before putting them back into service.

“Something all people feeding birds should be doing is keeping any structures involved in feeding really clean, as disease is a potentially big issue.”

Sources:

Josie A. Galbraith, Jacqueline R. Beggs, Darryl N. Jones, and Margaret C. Stanley (2015). Supplementary feeding restructures urban bird communities, Proceedings of the National Academy of Sciences, published ahead of print on 4 May 2015, doi:10.1073/pnas.1501489112 [₤]

Josie Galbraith emails & tweets; [4 & 5 May 2015]

Also cited:

Survey of Fishing, Hunting, and Wildlife Associated Recreation–National Overview 2007. (2006). U.S. Fish and Wildlife Service. [Open access PDF]

Department of the Environment, Food and Rural Affairs (DEFRA) (2002). Working with the grain of nature, DEFRA Publications, London. [Open access PDF]

Glue, David (2006). Variety at winter bird tables, Bird Populations, 7:212-215. [Open Access PDF]

Fuller R.A., Paul R. Armsworth, Olga Barbosa & Kevin J. Gaston (2007). Garden bird feeding predicts the structure of urban avian assemblages, Diversity and Distributions, 14 (1) 131-137. doi:10.1111/j.1472-4642.2007.00439.x [₤]

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This piece has been edited and reformatted from the original.

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Grrlscientist can be found on on her eponymous Guardian blog, and she’s quite active on twitter: @GrrlScientist.

Posted in Animalia, Birding, Birds, Birds | Tagged , , , ,

Beatboxing birdsongs of New York

SUMMARY: In these fascinating videos, we see how one man’s quest to merge two passions — bird watching and beatbox music – has created an experimental new form of music

Ben Mirin, birder and professional beatboxer.

Ben Mirin, birder and professional beatboxer.

I love beatboxing, but as an ornithologist and birder, I am absolutely delighted by this amazing experiment that a fellow New Yorker, Ben Mirin, is working on: he is using birdsong produced by birds that can be found in New York state as the inspiration for his beatboxing.

Mr Mirin is a professional beatboxer, freelance writer and videographer who combined his two passions — beatboxing and birding. Born in Boston, he relocated to New York City in 2013. At that time, he began composing music using local bird songs and his own voice to merge his two interests into a single idea.

“The result was a union of two musical languages whose sounds carry meanings and messages beyond the flow of a melody or the rhythm of a beat”, writes Mr Mirin on his blog, Wingbeat.

Recently, Mr Mirin has expanded his beatboxing to encompass his other passion; conservation. To do that, he is exploring how to incorporate other animal sounds into his musical compositions.

Want to hear more beatbox birdsongs? This fun video, which features birdsongs that can only be heard in wetland habitats, was created by Mr Mirin especially to celebrate World Wetlands Day 2015:

The birdsong samples were created from field recordings courtesy of the Macaulay Library at the Cornell Laboratory of Ornithology.

Ben Mirin writes the blog, Wingbeat, and, appropriately enough, you can also find him on Twitter @BenMirin and on a flock of other social media.

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This piece has been edited and reformatted from the original.

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Grrlscientist can be found on on her eponymous Guardian blog, and she’s quite active on twitter: @GrrlScientist. She sometimes lurks on social media; facebook, G+, LinkedIn, Pinterest.

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BoobSaver 5K

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In honor of Friday’s National Mammogram day, Jack Black gets a mammogram in honor of the Men for Women Now campaign, a collaboration between the Noreen Fraser Foundation and SocialVibe to fund women’s cancer research. Jack co-wrote this video where he encourages men to “get off our lazy butts…”

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Brother Sam Presents the Oral Awards

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This hilarious video is a special program featuring Sam Singleton Atheist Evangelist as he institutes a new award in honor of outstanding achievement in the oral arts. Starting with Oral Roberts, who was commanded by Jeebuz to “get your ass out there and evangelize!!”
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Today’s Mystery Bird for you to Identify

You will find the discussion at Maniraptora.

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Brostitution and Brostitutes

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Okay, speaking of “what is family”; this video is a humorous trailer for an imaginary documentary that takes a closer look at the seedy world of brostitution and brostitutes. Brostitutes are men who provide companionship to lonely men .. scientists and doctors, for example .. in exchange for money. This film digs deeper than any other film has when it comes to this secret world of bro-on-bro non-sexual love for profit.
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The Empathic Civilisation

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This video animates a presentation by bestselling author, political adviser and social and ethical thinker, Jeremy Rifkin. It presentes his investigations into the evolution of empathy and the profound ways that it has shaped our development and our society.
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