Picture This

The postman knocked on the door. Katrina had emailed to say there was a package on the way. I slid the precious contents from the tube. This was rather like Christmas.  But here was a job for an expert picture framer, so I made my way to Garstang Picture Gallery. But bad news, they were busy and I must wait three weeks for the framing job.

Picture This

Meanwhile here on the Lancashire coast, where many, many thousands of wild Pink-footed Geese spend the winter and where their calls and daily flights are part of everyday life, it is impossible not to become a fan of these rather special creatures. 

Into the New Year when the shooting season is over and the daily legions of wildfowlers lay down arms, our geese become comparatively less wild. They quickly learn that not every human wishes them harm and perhaps understand that us birders thrill to the sight and sound of their daily coming and going. 

With luck, and if the feeding on new grass or unharvested potatoes is especially good, the geese become tolerant of an inquisitive car with a telescope poked from a partly lowered window.  Mostly the Lancashire hordes are “pinkies”, but with the occasional bonus of a Bean Goose, White-fronted Goose or Barnacle Goose hidden in the mix. Very often, a gaggle of Greylags tag along for the daily ride. 

Pink-footed Geese 

White-fronted Goose 

Pink-footed Goose 

Bean Goose

Greylags

Barnacle Goose

To whichever species they belong, all geese share certain characteristics. Geese are highly intelligent team players - protective of their environment, inquisitive, amicable, loyal, caring, helpful, but aggressive where necessary.  Geese have eyesight more highly developed than man or dog, with hearing superior to both; hence the employment of domesticated geese as security guards in many situations, not least in the average farmyard where urban thieves, naïve in the ways of the countryside, may get a bite on the leg for their trouble. 

Yes, I'm a devotee of geese. So when I saw author and illustrator Katrina’s van Grouw’s stunning evocation of geese in her new book Unnatural Selection, I made enquiries as to how I might acquire a copy.

Unnatural Selection is the finest book I have read in many a year. Read my original review at Another Bird Blog.  

Goose Ancestry 

To cut this long story short, there’s now a new picture hanging in the hallway, a signed copy of the above in pride of place, visible from my workspace. I can't thank Katrina enough for the time and trouble she took to send me this wonderful picture. 

Goose Ancestry by Katrina van Grouw 

As you will see, Katrina is a brilliant artist. She also has a way with words that makes her prose equal to her artistry. Here she is on domestic geese, taken from “Unnatural Selection”, a passage that effectively explains the origins of the multitude of farmyard geese that cause all sorts of trouble to new (and sometimes not so new) birders. 

“By defining a species as something that can only interbreed (and produce fertile offspring) with others of the same species, you’re effectively denying any possibility that species can interbreed — otherwise, they wouldn't be species. But animal species do hybridize, and they do produce fertile offspring. And for evidence, you only need to look, once again, to domesticated animals. 

Take geese, for example. Geese are among the few domesticated animals that have not just one but two wild ancestors. I don’t just mean subtle genomic differences that suggest a hybridization event early on in their domestication history. No, pure-bred geese that derived from two totally separate species — the Swan goose, Anser cygnoides, from Central Asia and the Greylag goose, Anser anser, from Central Europe — hybridise readily and regularly. 

Out of any mixed farmyard flock, it’s normal to find a substantial number of hybrids between the two. Even several recognised breeds, like the Steinbacher from Germany, are hybrids between the two parent species. The domesticated forms of the Swan goose are the sublimely elegant Chinese goose and the more heavyweight African goose. 

Although Swan geese have a slender head and bill like a swan, with only a subtly raised “knob” at the base of the bill, both of the domesticated varieties have a deeper skull, and the bill knob is positively enormous. Both, however, share the Swan goose’s unusually smooth silky neck feathering and (unless they’re leucistic) the deep chocolate brown stripe running from the crown to the base of the neck. Greylag geese have a much deeper, more powerful bill than Swan geese and have the deeply furrowed feathering down the neck so typical of the majority of goose species." 

Unnatural Selection  

To read more about Katrina van Grouw visit  her web page.

Unnatural Selection is available from Princeton Press at £35 or Amazon at about £22.

I am not a fan of huge global companies dominating world trade to the detriment of small players whereby I deleted my Amazon account years ago. But I understand that in this case at least, the author receives the same payment as someone buying from the publisher. So there is a monetary saving to be made for those who have no issues with using Amazon.

This book would make a great Christmas or birthday gift to any aspiring author or artist.  A student of biology, science, history, or evolution would find this book indispensable. I am none of those things but I was enthralled by this most remarkable of books and I wholeheartedly recommend it to readers of Another Bird Blog. 

Linking today to Stewart's World Bird Wednesday.

Iceland Jobs

We were pretty keen to get out ringing this week but a steady wind of 15-20 mph made it impossible for days on end.  The usual check on late Wednesday afternoon suggested those pesky isobars might just pull apart for Thursday morning, so I arranged to meet Andy up at Okenclough for a ringing session. 

"Maybe" weather

Back home there was a hint of (unforecasted) drizzle at the off. As I drove up to Oakenclough, 600ft above sea level, the drizzle intensified with a wind from the North West at about 8-10mph. At first “light” there was 100% low cloud with light but spasmodic drizzle. 

But we stuck to the task in hand, the drizzle eased as the light improved slowly and we packed in about 11 am. During the whole time there was very little visible migration but in the circumstances we managed a reasonable catch, mainly Redwings. 

The birds caught tell the story of the morning: 17 Redwing, 4 Coal Tit, 2 Goldfinch, 2 Goldcrest, 2 Blue Tit, 1 Great Tit. 

In the heavy cloud conditions with very low visibility the visible migration of thrushes was virtually zero. We had maximum counts of 180 Redwing and 40 Fieldfare, mostly arriving from unseen directions as they dropped through the cloud cover.  Otherwise, the count of small birds was negligible. 

The field sheet shows how at least three of this morning’s Redwings were of the Icelandic sub-species, Turdus iliacus coburni, rather than the nominate European race Turdus iliacus. 

Spot the Iceland Jobs 

Birds of the Icelandic subspecies are marginally larger and darker than nominate birds from Europe but only around 10-15% of Icelandic birds have longer wing lengths, so relatively few are separable on size. 

But this morning it was noticeable how at least 50% of Redwing wing lengths were in the 120’s rather than the mid to late teens of recent ringing sessions. The three biggest came in at wing lengths of 129 mm, 127 mm and 124 mm with corresponding respective weights of 76.5 gms, 68.5 gms and 68.9 gms. Compare these three monsters with three of the smallest – 113 mm with 56.7 gms, 117 mm with 58.9 gms, and 117 mm with 61 gms. 

Icelandic Redwing 

European Redwing 

We’ll be trying again soon so let’s hope for a few windless days and more light for more photos.

Linking today to Eileen's Blogspot and Anni's Birding.

Extinct? Who Cares?

“The sixth mass extinction is under way, this time caused by humans. A team of researchers have calculated that species are dying out so quickly that nature's built-in defence mechanism, evolution, cannot keep up. If current conservation efforts are not improved, so many mammal species will become extinct during the next five decades that nature will need 3-5 million years to recover to current biodiversity levels. And that's a best-case scenario.” 

Date: October 15, 2018 

Source: Aarhus University 

"There have been five upheavals over the past 450 million years when the environment on our planet has changed so dramatically that the majority of Earth's plant and animal species became extinct. After each mass extinction, evolution has slowly filled in the gaps with new species. 

The sixth mass extinction is happening now, but this time the extinctions are not being caused by natural disasters; they are the work of humans.  A team of researchers from Aarhus University and the University of Gothenburg has calculated that the extinctions are moving too rapidly for evolution to keep up. 

If mammals diversify at their normal rates, it will still take them 5-7 million years to restore biodiversity to its level before modern humans evolved, and 3-5 million years just to reach current biodiversity levels, according to the analysis, which was published recently in the scientific journal, PNAS." 

Some species are more distinct than others 

"The researchers used their extensive database of mammals, which includes not only species that still exist, but also the hundreds of species that lived in the recent past and became extinct as Homo sapiens spread across the globe. This meant that the researchers could study the full impact of our species on other mammals. 

However, not all species have the same significance. Some extinct animals, such as the Australian leopard-like marsupial lion Thylacoleo, or the strange South American Macrauchenia (imagine a lama with an elephant trunk) were evolutionary distinct lineages and had only few close relatives. When these animals became extinct, they took whole branches of the evolutionary tree of life with them. We not only lost these species, we also lost the unique ecological functions and the millions of years of evolutionary history they represented. 

"Large mammals, or megafauna, such as giant sloths and sabre-toothed tigers, which became extinct about 10,000 years ago, were highly evolutionarily distinct. Since they had few close relatives, their extinctions meant that entire branches of Earth's evolutionary tree were chopped off" says palaeontologist Matt Davis from Aarhus University, who led the study. 

And he adds: "There are hundreds of species of shrew, so they can weather a few extinctions. There were only four species of sabre-toothed tiger; they all went extinct." 

Long waits for replacement rhinos 

"Regenerating 2.5 billion years of evolutionary history is hard enough, but today's mammals are also facing increasing rates of extinction. Critically endangered species such as the black rhino are at high risk of becoming extinct within the next 50 years. Asian elephants, one of only two surviving species of a once mighty mammalian order that included mammoths and mastodons, have less than a 33 percent chance of surviving past this century. 

The researchers incorporated these expected extinctions in their calculations of lost evolutionary history and asked themselves: Can existing mammals naturally regenerate this lost biodiversity? 

Using powerful computers, advanced evolutionary simulations and comprehensive data about evolutionary relationships and body sizes of existing and extinct mammals, the researchers were able to quantify how much evolutionary time would be lost from past and potential future extinctions as well as how long recovery would take. 

The researchers came up with a best-case scenario of the future, where humans have stopped destroying habitats and eradicating species, reducing extinction rates to the low background levels seen in fossils. However, even with this overly optimistic scenario, it will take mammals 3-5 million years just to diversify enough to regenerate the branches of the evolutionary tree that they are expected to lose over the next 50 years. It will take more than 5 million years to regenerate what was lost from giant Ice Age species." 

Prioritizing conservation work 

"Although we once lived in a world of giants: giant beavers, giant armadillos, giant deer, etc., we now live in a world that is becoming increasingly impoverished of large wild mammalian species. The few remaining giants, such as rhinos and elephants, are in danger of being wiped out very rapidly," says Professor Jens-Christian Svenning from Aarhus University, who heads a large research program on megafauna, which includes the study. 

The research team doesn't have only bad news, however. Their data and methods could be used to quickly identify endangered, evolutionarily distinct species, so that we can prioritise conservation efforts, and focus on avoiding the most serious extinctions.

As Matt Davis says: "It is much easier to save biodiversity now than to re-evolve it later." 

Expect The Unexpected

Five-fifteen. The alarm buzzed. “What would the day bring?” With luck the forecasts had been right, so through the "office" window I checked the darkened trees for signs of sway. They looked still, while above the street light there were breaks in the ghostly cloud. I heaved a sigh of relief, prepared for the off and for the 35 minute drive up to Oakenclough. For a ringer, the anticipation, the excitement of expecting the unexpected never quite goes away. 

At Okenclough it was still dark at 0630 as outer branches stirred ominously. It was more like 10-12 mph than the 6mph decreed by the experts. That 4+ mph can make a difference when birds with powerful eyesight can spot movement in the fine mesh of a mist net. 

Soon after dawn Redwings arrived. We caught a few in the dark as they continued to arrive in dozens and low hundreds, mostly from the north-west. Fieldfares began to arrive a little later but not in the same numbers as Redwings and certainly not in the numbers we witnessed on Thursday. By 10 am we had caught 14 Redwings and zero Fieldfares, despite counting 900 and 300 respectively. 

About 1030 it was as if someone dropped a curtain to stem the hitherto very visible migration. Birds passing through or overhead dwindled to near enough zero and it was time to pack up from what had been a disappointing catch of 14 Redwing, 2 Goldcrest, 1 Chiffchaff, 1 Treecreeper, 1 Goldfinch, 1 Blue Tit, 1 Long-tailed Tit. 

Chiffchaff 

Treecreeper 

Redwing 

As the figures above suggest, birds other than Redwings and Fieldfares were hard to come by. It was as if all were in a hurry to reach their unknown destination with very few stopping off in our ringing site. As earlier in the week, we noted a strong movement of Woodpigeons heading south-west – circa 550 in 3+hours. 

In addition to thrushes we recorded approximately 60 Chaffinch, 20 Goldfinch, 6 “Alba” Wagtail, 4 Lesser Redpoll, 3 Siskin, 1 Bullfinch, 1 Reed Bunting, 1 Kestrel, 2 Sparrowhawk. 

Overall we enjoyed an exhilarating week of ringing with 157 birds caught, 99% of which were involved in active migration. Every one of those birds now carries a unique ring, the data associated with each capture is held on the National database, and every one of those birds could well provide more information in the coming days, weeks and years. One already has. 

A Lesser Redpoll Andy caught on Wednesday 17 October 2018, ring number ADA0166, had been ringed 364 days earlier on 18 October 2017 at Middleton, Morecambe Bay, Lancashire. 

On the way home but by barely stopping I clocked up 4 Kestrels, 2 Buzzard and 1 Sparrowhawk. Also, 125 Whooper Swans on Pilling Moss – our winter swans are back with my best count so far. 

Whooper Swans

There's more soon from Another Bird Blog.  Expect the unexpected and you won't be disappointed.

Linking this post to Anni's Birding Blog. 

Different Day, Different Birds

Monday saw a catch of 33 birds up at Oakenclough. Domestic commitments meant I couldn't make it on the next suitable morning, Wednesday, even though I was raring to go. Andy went alone and caught 60 birds, including another 15 Redwings and 8 more Lesser Redpolls. 

With so many millions of birds on a migratory push through the UK and Europe at this time of year there is a guarantee that each visit brings new birds to our nets. 

So with yet another excellent forecast we arranged to meet up again at Oakenclough on Thursday. We were joined today by Bryan H. At 0700 there was a slight breeze from the east with nil cloud and a temperature hovering around 2°C. 

The lack of cloud meant that migration might at the least prove hard to pick up or even non-existent if birds had found their way through the clear starry night. We needn't have worried too much as although small passerines were scarce there was a huge rush of northern thrushes and we kept busy throughout. 

By 11 am we had counted a minimum of 900 Fieldfare and 400 Redwing passing overhead. The thrushes were arriving from east and south-easterly directions and not from the north as we perhaps thought they might. This is suggestive of east coast arrivals with subsequent travel over the Pennines on west and south-westerly headings. 

Although Fieldfares easily outnumbered Redwings in the overall count, we caught proportionally more Redwings. This is due to the larger size of the Fieldfare and its ability to escape from a mist net, but also to its overall wariness when man is around. We also think that Fieldfares have superior eyesight to Redwings and are less likely to find themselves in a mist net, even in the half light of morning. In many countries of Europe, Fieldfares are hunted mercilessly, as are Redwings.  

Totals today: Redwings made up 50% of the catch - 42 birds of 10 species: 22 Redwing, 3 Fieldfare, 1 Blackbird, 5 Goldfinch, 3 Great Tit, 2 Chaffinch, 2 Lesser Redpoll, 2 Coal Tit, 1 Blue Tit, 1 Wren, 

Field Sheet (Part)

The below Fieldfare is a first year male - amount of black in crown feathers, contrast in primary and secondary coverts. Tail feather shape. 

Fieldfare

Fieldfare 

Fieldfare

The Redwing below is a classic first year. Note the “pointy” tail feathers and the whitish notches on the tertial feathers. 

Redwing 

First year tail - Redwing 

Adult tail - Redwing 

Wing Tracts 

Unlike the last two visits here, Lesser Redpolls proved hard to come by. Their visible migration was zero, likewise Chaffinches, even though we caught two of each species. 

Lesser Redpoll 

Out of interest, and to remind ourselves that the Common Redpoll and the Lesser Redpoll are now lumped together (again). 

The taxonomy of redpolls remains unsettled, part of an ongoing debate that recognises several different but very closely related forms of redpolls, considered as anything from one to five species. After a number of attempts and changes of mind by “experts”, the UK/European Lesser Redpoll is now assigned as a geographic sub-species of Common Redpoll by recent genome wide analyses that found differences in gene expression but no genetic divergence. This gives credence to the idea that the essentially plumage forms (like our own rather brown Lesser Redpoll) originated quite recently within a single interbreeding lineage and do not represent species boundaries. 

Well, what do you know? The forecast is good again for Friday. Looks like we are in for more different birds.

Linking this post to Eileen's Nature Blogspot.

Rare As Hen's Teeth

As predicted, a weekend of Storm Callum made for several grey, wet and windy days and left no chance of a ringing session. During this time it seemed unlikely that many of our target birds had made it south to Lancashire through such unfavourable weather systems, despite good numbers of Redwings, Bramblings and Fieldfares in the Northern Isles of Scotland, some 6/700 miles away. 

Sunday afternoon was bright and sunny to further heighten expectations for Monday morning, already pencilled in as the first “probable” day for a rush of birds from the North. At 0630 I met Andy at our regular ringing site near Oakenclough, a hamlet that lies on the very edge of the Pennine Hills. 

Before today at this site we’d handled over 620 birds for the year but with luck September and October see a major arrival of many birds into the UK – mostly finches and thrushes, but also buntings and eastern warblers. This is our chance to bump up the totals and gain a few extra species. 

But it wasn't the anticipated Redwings that topped our catch but our old friend the Lesser Redpoll, a species hard to come by this autumn. Total birds caught - 36 of 11 species. 10 Lesser Redpoll, 5 Redwing, 5 Chaffinch, 4 Blue Tit, 2 Goldcrest, 2 Goldfinch, 2 Long-tailed Tit, 2 Great Tit, 2 Coal Tit , 1 Robin, 1 Song Thrush. 

We can only guess why Lesser Redpoll have been conspicuously absent until today but it was good to see them back on site. We saw a total of about 45 this morning, the numbers made of several small flocks which began to arrive only after about 10 am. Our main theory for the lack of redpolls this year is that the hot summer and warm autumn to the north delayed their departure until now. The next few visits up here to Oakenclough should either confirm this or give yet more food for thought if we fail to catch more. 

Lesser Redpoll 

We counted approximately 70 Redwings this morning, less than we hoped for but still nice to see and examine. In what was a slight north-easterly breeze they arrived in small flocks from various compass points but gave little clue as to their routes of travel. 

Redwing 

The Redwings Turdus iliacus we see here have crossed the North Sea from Scandinavia & Russia and arrived in the UK on a broad front - west, central and east before some found their way into Lancashire via the coast or by travelling overland. Icelandic Redwings Turdus iliacus coburnii arrive about the same time by taking a westerly approach to Britain. This sub-species is darker overall, and marginally larger than the nominate Turdus iliacus. 

The two are hard to distinguish in the field but slightly easier in the hand, especially so with direct and immediate comparisons of several individuals. The five today were or all iliacus specimens confirmed by their “normal” appearance and biometrics. 

As autumn turns to winter, Redwings have largely finished their journeys and settle in the warmer and relatively frost-free areas away from the east coast. Hard weather may force them to migrate further, as Scandinavian/Russian birds continue west to Ireland or south into southern Europe. To some degree, Redwings can be somewhat nomadic, with individuals taking different routes in different years when leaving their breeding areas. 

The birding was pretty sparse this morning, the main components of visible migration being Woodpigeons and Chaffinches. Many Woodpigeons flew in a clear north to south west trajectory in groups of 10-60 individuals and a total count of 800/900 in the five hours of watch. Chaffinches totalled circa 150 individuals with once again a clear north to south movement of between 5 and 20 birds. 

Chaffinch

Other highlights included 4 Fieldfare, 3 Buzzard, 2 Great-spotted Woodpecker and a “ringtail” Hen Harrier. 

The Hen Harrier is as rare as hen’s teeth here on the edge of the infamous Bowland with its history of persecuting raptors, not least the Hen Harrier with its reputation of being partial to grouse chicks. 

Hen Harrier 

The harrier appeared from the north, quite high up and over the distant hills where it briefly interacted with a Buzzard. As it got closer but still fairly high we could see that it was a “ringtail”, a female or juvenile, and we watched as it drifted out towards the coast in a south-westerly direction. 

Almost certainly this was an individual from Scotland or the North East involved in visible migration. We were pleased that it chose not to linger in Bowland. 

Linking today with Stewart's World Bird Wednesday.

First Redwings

This has been a frustrating week of watching and waiting. Watching the weather forecasts and waiting for a morning that might allow Andy and me to get up to hills and catch winter thrushes. Redwings are on the move with small numbers reported from the east coast and Scotland early in the week with a possible “thrush-rush” on the cards any day soon. 

Tuesday evening and the forecast was “iffy” but with a chance of a couple of hours before an increase in wind speed later in the morning. After yet more chart watching we decided to go for Wednesday as the only likely day for at least a week ahead. 

We met up at 0630 to a 10mph south-easterly, far from ideal. But at least it was dry. 

We caught our first Redwings of the autumn but the overall catch was pretty poor due to the ever increasing wind that caused us to pack up at 1030. By this time it was pretty breezy and we reckoned the windy conditions had cost us 30 or more birds. 

We caught just 13 birds: 7 Redwing and then one each of Goldfinch, Chaffinch, Great Tit, Chiffchaff, Goldcrest and Sparrowhawk. 

The Sparrowhawk caught was a first year female. The two sexes take different size rings ,“E” or “D”, because of the different size of male and female and the equivalent variation in the diameter of their tarsi. 

Sparrowhawk 

Sparrowhawk 

In all we saw 70+ Redwings this morning, most arriving from the north, but some unseen. Otherwise, thrushes were absent apart from 2 Blackbirds, 2 Song Thrush and 1 Mistle Thrush. 

It’s a little early in the autumn for west coast Fieldfares despite the usual reports elsewhere of “fieldfares“. These are invariably distant Mistle Thrushes, a similarly sized thrush that at this time of year also migrates in small parties. 

Redwing 

Redwing 

Chiffchaffs continue to be scarce.  Today’s Chiffchaff, a tiny first year, was number 12 for the year at this site.  A very poor showing. 

Chiffchaff 

There seemed to be lots of finches on the move this morning, mainly Chaffinches flying low into what became a fairly stiff breeze. Small parties flew overhead from a north to south direction for at least three hours and totalled 140+ birds. None seemed to stop in the plantation as they hurried through and disappeared out of sight to the south. 

Additionally we noted 30+ Goldfinch, 20+ Linnet, 8 Pied Wagtail, 2 Jay, 1 Kestrel, 8 Lapwing.

Linking today to Anni in Texas and Eileen's Blogspot.

Recent Recoveries

There’s no birding or ringing for a day or two thanks to continuing poor weather so I’m posting information about a couple of recent ringing records. One is a Sand Martin at Cockerham quarry, the other a Linnet from our Linnet project at Gulf Lane, Pilling/Cockerham Marsh. 

Linnet 

We ringed Linnet number S800115 as a juvenile male on 10 August 2017- Biometrics: Wing: 81.0 mm. Weight: 17.8 g. Time: 10:00:00 hrs 

Our Linnet was recaptured on 04 May2018 at Walney Island Bird Observatory, Cumbria. Although the distance between the two points is negligible, the date of both the original ringing and the recapture are much more interesting. The month of August points to a juvenile dispersal, maybe from Cumbria but with a possibility that the bird’s place of birth was further north. The timing of its return on a northward track during May is within the peak of period of Linnet spring migration and when S800115 may have headed back to or near to its place of birth. 

I'm afraid that such recoveries often provide a few answers but inevitably throw up new questions. At least the bird is still in circulation and presents a small chance that should it be captured for a third time, more information on its travels may become known. This latest recovery fits into two previous recoveries and north/south movements to or from Gulf  Lane.

Linnet from Shetland 

Linnet to Lochinver

Linnet to Walney Bird Observatory

Duration: 267 days Distance: 23 km Direction: 300deg (WNW) Finder: Walney Bird Observatory, 9095 

Sand Martin 

On 23rd May 2018 we caught a French ringed Sand Martin at Cockerham Quarry.

Paris ringed Sand Martin

Sand Martin (Riparia riparia) - Ring no: 7193238 Ringing details- Age: 4 (adult) Ringing date: 10 August 2015 Site name: Hiers-Brouage, Charente-Maritime, France Ringer: Paris, -11

Sand Martin

Hiers-Brouage to Cockerham

Ring number 7193238 was recaptured at Cockerham on 23 May 2018. Duration: 1017 days Distance: 910 km Direction: 352deg (N)

The Rats Are Winning.

Grotty weather again today, so nothing doing in the birding or ringing stakes.

Instead, here’s an interesting study on cats versus rats. Cat lovers and bird lovers rarely agree, but in this case it seems that pussy cats are not the ultimate rat catchers but prefer instead to eat a bird or a mouse. 

Pussy Cat

Journal Reference: Michael H. Parsons, Peter B. Banks, Michael A. Deutsch, Jason Munshi-South. Temporal and Space-Use Changes by Rats in Response to Predation by Feral Cats in an Urban Ecosystem - Frontiers in Ecology and Evolution, 2018. 

"Like any prey, rats overestimate the risks of predation. In the presence of cats, they adjust their behaviour to make themselves less apparent and spend more time in burrows," says the study's lead researcher Dr. Michael H. Parsons, a visiting scholar at Fordham University. "This raises questions about whether releasing cats in the city to control rats is worth the risks cats pose to wildlife." 

People have long associated cats as the natural enemy of rats. However Australian and US researchers say cats prefer smaller, defenceless prey such as birds and smaller native wildlife -- which makes cats a threat to urban ecosystems. 

"New Yorkers often boast their rats 'aren't afraid of anything' and are the 'size of a cat'," says Parsons. "Yet cats are commonly released to control this relatively large, defensive and potentially dangerous prey." 

Brown Rats

"Until now, no one has provided good data on the number of city rats killed by cats," adds co-author Michael A. Deutsch, from Arrow Exterminating Company.  "But the data have been very clear as to the effect of cats on native wildlife." 

When feral cats invaded a New York City waste recycling centre, the researchers took the opportunity to correct the record. Their team was already studying a colony of more than 100 rats living inside the centre, by microchipping and releasing the animals to study their life history. When the cats entered the research area, they set up motion-capture video cameras to quantify the effect of the cats on the rats -- the first time this has been studied in a natural setting. 

"We wanted to know whether the number of cats present would influence the number of rats observed, and vice versa," says Parsons. "We were also interested whether the presence of cats had any effect on eight common rat behaviours or their direction of movement." 

The researchers examined 306 videos taken over 79 days. Although up to three cats were active beside the rat colony each day, only 20 stalking events, three kill attempts and two successful kills were recorded in this time. Both kills took place when cats found rats in hiding; the third attempt was an open-floor chase where the cat lost interest. 

The videos also revealed that in the presence of cats, the rats spent less time in the open and more time moving to shelter. "The presence of cats resulted in fewer rat sightings on the same or following day, while the presence of humans did not affect rat sightings," says Parsons. In contrast, the number of rats seen on a given day did not predict the number of cats seen on the following day. 

"We already knew the average weight of the rats was 330 g, much more than a typical 15 gm bird or 30 gm mouse," says Parsons. "As such, we expected a low predation rate on the rats -- and our study confirmed this." 

"We are not saying that cats will not predate city rats, only that conditions must be right for it to happen," adds Deutsch. "The cat must be hungry, have no alternative less-risky food source, and usually needs the element of surprise." 

The findings could explain why people continue to release cats as "natural" rat control tools. "People see fewer rats and assume it's because the cats have killed them -- whereas it's actually due to the rats changing their behaviour," says Parsons.

"The results of our study suggest the benefits of releasing cats are far outweighed by the risks to wildlife," he adds. The research team plans to continue collecting data as part of their long-term study and will update their findings as new information becomes available. 

Pussy Cat

"Much more research is needed to better understand the city rat problem, we hope our successes will compel others to perform similar studies in other venues," says Parsons. But for now, in the battle of New York City cats and rats it appears the rats are winning. 

Linking today to Anni's Blog and Viewing Nature With Eileen.. 

Why Skiathos?

Keen eyed readers will note how the header picture changed. I swopped the Glasson Dock Common Tern for a Skiathos Yellow Wagtail. 

Yellow Wagtail (Motacilla flava) is familiar to British birders but throughout Europe there are many overlapping races and intergrades of Yellow Wagtail, whereby literally dozens of races and sub-species have been described. This makes identification and assignation difficult, especially at migration time in Central Europe in the case of juveniles like the one shown.

I'm thinking that the header bird, the one below, may be Motacilla flava beema, also known as Sykes’ Wagtail, especially since other Yellow Wagtails I saw fitted the same criteria. Yellow wag experts out there may wish to comment? 

Yellow Wagtail

Otherwise, birding on Skiathos Island proved rather unexciting during very hot, clear weather and wall-to-wall sunshine – not the best conditions for dropping migrants onto an off-shore island. So I returned home with very few bird pictures. 

We saw lots of Spotted Flycatchers, Whinchats, Yellow Wagtails, Red-rumped Swallows and Barn Swallows, together with Buzzards, Willow Warblers, Kingfishers and the inevitable Eleonora’s Falcons. Unlike other years Red-backed Shrikes were few and far between where by locals told of a long hot summer where a successful breeding season may have finished early. 

Spotted Flycatcher 

Red-backed Shrike 

A developing storm on our last day saw thousands of Red-rumped Swallows overhead as they descended below cloud level to escape the incoming turbulence. We left Skitahos just in time because since we returned home Cyclone Zorba laid waste to a number of places on the Peloponnese mainland including parts of Athens. 

There was a knock-on effect to Skiathos where we heard that tourists out to enjoy the last week of the Skiathos season have had a pretty raw deal from cloud, rain and wind.

Today, Sunday, from Skiathos. "The main road is closed at Acropolis, at Kolios and at Troulos due to flooding and water escaping from the mountain into the sea. Power disruptions due to the weather. 102 mm of rain today to add to the 53 mm of Saturday." 

Nonetheless we asked the lovely Anna to reserve our room for next year as we have no reason to doubt the question of “Why Skiathos?”. 

Why Skiathos?

Skiathos Town

No Name Gyros

Big Aselinos Beach

Skiathos 

Skiathos donkey

Bourtzi Skiathos

Ouzo

Yes, we will be back.  And very soon.

So will Another Bird Blog with more news, views and photos.

Linking this post to Stewart's World Bird Wednesday.