Seasonal Update (July 2023)


Mid-summer has arrived! July, the fourth of seven months with 31 days, was the year of Roman general Julius Caesar's birth, and so named in his honour by the Roman Senate during 44 BP. Prior to this re-naming, the month was called Quintilis, as the fifth month in the earliest Roman calendar. Here in the northern hemisphere, July is typically the warmest month, while it's the coldest month in the southern hemisphere, being the northern hemisphere's seasonal equivalent of January.

Weather update

May merged imperceptibly into June, with any early cloud burning back quickly to provide sunshine and clear blue skies for most of the country, the warmest temperatures in the west and south-west. Indeed, Cornwall, Wales and western Scotland were widely into the low to mid 20s Celsius (high 70s F), while a moderate easterly wind held back temperatures in the east. This warmth continued for the first half of the month, and we saw some significant thunderstorms push north and west throughout the course of the second weekend as temperatures in the south-east reached 32C (90F). Another week of dominant high pressure before Atlantic lows pushed eastwards during the fourth week, bringing some heavy and persistent rain, dropping temperatures by a couple of Celsius.

Early June saw heavy and thundery showers across the UK and much of Europe. - Credit: WX Charts

June ended with a series of low-pressure systems working their way from west to east, bringing rain to all, although the south and south-east of England saw relatively little, rather frustratingly for gardeners and water companies who had been hoping for some significant rain. Temperatures were back down around average for the time of year in the low 20s Celsius (low 70s F), although there were a couple of muggy nights during the final week before a cold front pushed in. Overall, the Met Office confirmed that this June is now the warmest on record in the UK.

Outside of the UK, after a hot summer and exceptionally dry winter and spring, parts of Spain were subjected to torrential rain that caused localised flooding. Finland saw extreme cold to start the month, with -7.7C (18F) recorded at Enontekiö Sanna on 1st June, beating the national cold record for the month set in 1962 at Inari Laanila. China's intense heatwave continued, with Dongchuan nudging over 42C (108F). Argentina also saw a very warm start to winter, with temperatures in the low to mid 20s Celsius and even some tropical nights, when temperatures didn't drop below 20C (68F). While parts of western Australia and New Zealand saw cold to begin June, central and eastern Australia broke several records as temperatures rose to 20C during the first two weeks of last month.

Intense wildfires have destroyed forests and homes across Canada and forced the evacuation of 20,000 people. Some 2,500 fires were reported to authorities, burning 4.7 million hectares (11.6 million acres), and the Canadian Interagency Forest Fire Center anticipates 2023 will be the worst wildfire season to date. The fires followed an unusually dry period in the southern parts of the Atlantic Region, which saw about half the expected rainfall. Eastern India was under one of the worst heat waves in its history, with records set for night and day as temperatures failed to drop below 30C (86F).

News and discoveries

Winging it. A whole host of genes combine to give us the morphology that we recognise as a human. Many of those genes are what we call planar cell polarity genes, and they help ensure that cells are pointing in the right directions - these genes explain why mammalian hairs all point in a certain direction, for example. Recently, researchers looking at the development of the enlarge pectoral (side) fins of skates found sections of DNA that had been broken up and moved around, a process involving the polarity genes. The scientists suggest that as one of these genes is active in the developing skate, but not in sharks, this might be the key to allowing the skate wings to all elongate in the same direction.

Scanning electron micrograph (magnified 500x) of pollen from a variety of common plants, including sunflower. - Credit: Dartmouth Electron Microscope Facility, Dartmouth College

Purgative pollen. There can be no doubt that many plants need bees to propagate, but new research suggests that pollen is more than just a meal ticket for these vital pollinators. We've known for a while now that feeding on certain types of pollen, from sunflowers in particular, seems to make bees less susceptible to some infections, but only now are we starting to understand why. A team led by Laura Figueroa at UMass Amherst in Massachusetts fed one group of bees whole pollen, another group were fed just the spikey shell of the pollen, and a third group the inner metabolite centre of the pollen. The results show that bees consuming the spiny shells or whole pollen had 81-94% fewer Crithidia bombi, a common parasite, in their guts than the bees eating only the metabolite cores. The suggestion is that the spikes on the pollen may irritate the gut lining, causing parasites to be expelled more rapidly.

Octopus oncology. A chemical compound called N-(2-ozoazepan-3-yl)-pyrrolidine-2-carboxamide, or ozopromide for short, found in the ink sacs of common octopuses (Octopus vulgaris), has recently come under scrutiny for its anti-cancer properties. Scientists at the University of Sonora in Mexico have been able to synthesize the compound in their lab and used it to kill cancerous cells while leaving healthy cells untouched. Alongside its potential to kill cancer cells, the ozopromide also appeared to reduce inflammation and improve the overall healing following the cell death.

Clean-up crew. Worms of the Osedax genus, meaning “bone eater” in Latin, are key players in the recycling of bones that fall to the sea floor. These creatures were initially discovered feeding on whale bones, but fossil data suggest that they've been around since the Cretaceous, so well before the first whales appeared. Now new research suggests that they're also able to extract the collagen from shark skeletons, which presumably also helps keep them going between whale falls. Scientists at the University of California, San Diego sunk bags of shark jaws down to 1,000 m (3,280 ft.) into Monterey Bay and returned eight months later to find that the worms had eaten virtually all the jaws and started colonising the teeth. The worms secrete acid that penetrates bone in the roots of the teeth, but they apparently can't dissolve the enamel on the crowns, which is harder than the bone.

Seasonal highlight – Red kites (Milvus milvus)

For decades the high-pitched nasal cry of the red kite signified that you were in the valleys of mid-Wales. In recent years, however, kites have made something of a comeback in the UK and are widely accepted to be one of our greatest bird of prey conservation successes. So, what is a red kite? These are large raptors, with a body length of around 65 cm (25 in.) and a wingspan of up to 180 cm (6 ft.), are about 30% larger than the more commonly encountered buzzard (Buteo buteo). Red kites get their name from the rusty, chestnut red-brown colour of their body and upper tail feathers; the underside of the tail is creamy white, and the head is pale grey with brown streaking. When in-flight, the primary (wingtip) feathers of the kite are more prominent and the wings proportionally longer than those of buzzards, while the trailing edge of the tail is typically folded in to form a v-shape, rather than rounded as it is in the buzzard. Indeed, buzzards and kites can often be separated in the air by only a cursory look at the tail position.

Red kites are increasingly common in England, having suffered widespread decline through persecution. - Credit: Marc Baldwin

Red kites were first formally described by the Father of Taxonomy Carl von Linné in 1758, assigned the binomial name Falco milvus. Falco is Latin for “falcon”, derived from falcis, meaning “sickle” and a reference to their claws, while milvus is the Latin name for a kite. As the field of taxonomy grew, the Falco genus became too restrictive to properly reflect the diversity seen within the raptors, and the kites were split out into their own genus, Milvus, first proposed by French naturalist Bernard Germain de Lacépède in 1799. Today, kites join many other well-known birds of prey in the Accipitridae family, which contains many of the diurnal (day-active) falcons, eagles, and hawks. There are currently eight sub-families within the Accipitridae, including the Buteoninae (buzzards), the Accipitrinae (hawks including the sparrowhawk and goshawk) and the Milvinae. The genus Milvus contains four species: the black kite (Milvus migrans), yellow-billed kite (M. aegyptus), black-eared kite (M. lineatus) and, of course, the red kite.

Archaeological evidence tells us that Red kites have been in Britain since the last inter-glacial period some 120,000 years ago, although, being a bird of open country, its range was presumably restricted by the degree of forest cover on the island during this time. Indeed, the kite's range appears to have expanded as Neolithic famers started clearing large swathes of forest so the land could be used for agriculture around 2,500 B.P., after which it appears to have flourished and, by the Middle Ages it was a common sight in many towns and cities, including London. The bird was also capturing public attention by this time and Shakespeare makes no fewer than 15 references to kites in his works, including describing London as 'a city of crows and kites'. In 1544, William Turner wrote of how Red kites were a nuisance in England:

Organised feeds of red kites, such as at Bwlch Nant yr Arian, attracts birds from a wide local area. - Credit: Marc Baldwin

For such is the audacity of our kites that they dare to snatch bread from children, fish from women and handkerchiefs from off hedges and out of men's hands. They are accustomed to carry off the caps from men's heads when they are building nests.”

It seems that kites were once as common a sight in cities as pigeons are today, where they fed on our waste, including bodies discarded in the street. Indeed, it's widely considered that the first problems for the kite in Britain came with the drive to clean up our cities; London's streets being cobbled and drained and waste being disposed of more hygienically ultimately resulted in less food for these birds. Worse came in 1566, when they were added to the list of noyfull Fowles and Vermyn—essentially a list of vermin species for which a bounty was paid for their destruction—for their alleged habit of taking chickens and rabbits. The result was thousands of birds being shot and poisoned during the 16th and 17th centuries. Kites, in common with most raptor species, were also heavily persecuted by gamekeepers who considered them a threat to gamebirds. Records are somewhat sketchy, but it seems that kites were probably extinct from England by 1879, excluding a couple of isolated records of a pair nesting in Devon (1913) and a pair in Cornwall (1920). It seems that kites had gone from Scotland by 1890, although records suggest a brief recovery during WWI as gamekeepers were called to serve in the armed forces. There is some dispute as to whether kites were ever common birds in Ireland, some suggesting it was vagrant at most, but either way the species appears to have become extinct here by the early 1800s. Kites also suffered significant losses in Wales but, thanks to the 'protection bounties' started in 1903 and paid by what would later become the RSPB, they weren't completely lost from here and, in his 1992 book Birds of Prey of the British Isles, Brian Martin notes:

In 1905 there were perhaps nine, certainly no more than twelve kites left in Britain, in the upper part of the Towy Valley, and it is only because of huge effort by private individuals who first provided protection, then later the RSPB with sophisticated electronic equipment, that the bulk of egg-thieves have been kept at bay.”

Red kite chick in nest. - Credit: Sharon Scott

Egg-collecting remains a serious problem faced by many raptors, and since 1905 the population of kites in Wales suffered many setbacks including egg theft, pesticides and other toxic chemicals, and the myxomatosis outbreak which saw a catastrophic decline in rabbits. Despite substantial re-forestation, which provided food in the form of voles, the kite population continued to do poorly and, in 1986, wild eggs were taken from nests and incubated in captivity in a bid to improve breeding success, with limited success. A break came in form of introductions from the continent. In June 1989, ten young kites were flown into Scotland by the RAF from Sweden; six were released in Scotland and four in England (The Chilterns). Sadly, one bird was poisoned by a gamekeeper soon after release, although he was heavily fined for this, but overall, the survival of the released birds was good. Subsequent releases yielded similar success, including 19 Swedish birds released in Scotland and 11 Spanish (plus two Welsh) birds released into England during July 1990. By 1991 there were an estimated 76 pairs in the UK, which fledged a total of 62 young, and the British population was put at 431 breeding pairs in 2000. Persecution is still a problem for all raptors, including kites, despite being punishable by law, but in general the population appears to be doing well. The RSPB currently gives a population estimate of about 2,000 and, on their website, list the distribution as:

Buckinghamshire/Oxfordshire area, Hertfordshire, Northamptonshire, Yorkshire, Gateshead, Northumberland and the Newcastle area and Grizedale Forest in Cumbria. The Scottish population is centred around the release sites in Dumfries and Galloway, Stirling-shire and west Perthshire, around Black Isle in Ross-shire, and on the outskirts of Aberdeen City.”

Red kites are also seen here in Hampshire and there are now reports pairs breeding down here near Southampton. Kites can also now be found in Ireland following the release of 30 Welsh birds at County Wicklow during July 2007.

Red kites begin breeding flights, involving much calling and wing displaying, during March and a clutch of one to three (rarely up to five) eggs are laid during mid-April. Incubation takes about 38 days and is done primarily by the female, who is supported by food brought in by the male. Once the eggs have hatched the male alone brings food for the next two weeks, which the female tears up and feeds to the chicks; after this both parents will hunt. Kites are very sensitive to disturbance when nesting and this can influence their fledging time. Martin notes:

Fledging can be very long - anything from 48 to 70 days, according to food supply and disturbance. Once airborne, the young become independent in about a month.”

Red kites often snatch prey from the ground and feed on the wing. - Credit: Ian Worsley (CC BY-NC-ND 2.0)

Kites are supreme scavengers, and a considerable proportion of their diet is carrion, which makes them very susceptible to poisoning, both intentional and accidental (e.g., taking poisoned rats). Roadkill provides a ready source of carrion, and in some areas red kites are now more often seen along main roads and motorways than kestrels. Along with carrion, however, kites will take invertebrates (particularly earthworms, grasshoppers, butterflies and beetles) and will also predate birds and small mammals. Kites are known to take most bird species up to about the size of a chicken, including chickens, starlings, pheasants, lapwings, rooks and black-headed gulls. Voles, moles, mice, young hares (leverets), rats, shrews and rabbits are among the mammals taken and one study in eastern France found that 94% of the kites' diet was water voles (Arvicola terrestris) during a population explosion of these rodents in 2008. Snakes, lizards, frogs, and toads may also be taken if the opportunity presents itself and food may be stolen from other birds including other kites, peregrines, crows and herons.

Overall, the red kite is a stunning bird of prey and for many a welcome part of the British landscape. If nothing else, this raptor serves as a reminder that, if properly managed and resourced, we can make a success of reintroducing and boosting wildlife populations in Britain. The red kite is no longer listed by the ICUN as a globally threatened species, although its large historical declines in Britain warranted its inclusion as a Bird of Conservation Concern and it is also a Species of European Conservation Concern.

For a round-up of Britain's seasonal wildlife highlights for mid-summer, check out my Wildlife Watching - July blog.

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