A slow start to spring

Despite the tantalizing period of exceptionally early spring warmth, it has been something of a slow start to the season. There have been some early nests, with young Robins, Song Thrushes and Blackbirds evident in many gardens across the county, but other individuals were held up by the returning cold conditions. Now, however, it feels as if the pace is quickening.

We have seen a succession of arrivals, as returning summer migrants have been quick to settle on favoured breeding territories and deliver song. The Chiffchaffs were the first of these to be noticed here, around the brecks, followed by Woodlark, Blackcap, Willow Warbler and, most recently, Whitethroat. Early Reed and Sedge Warblers appeared late-month, with numbers of these reed- and sedge-bed songsters now increasing. The hirundines (swallows and martins) were slow to return in numbers and my first sightings of these summer visitors were behind those of recent years.

We have also had a smattering of passage migrants, in particular a good arrival of Ring Ouzels. These striking thrushes resemble a large Blackbird but with beautiful sculptured plumage markings and, in adult males, a white crescent around the throat. We have also seen some less common visitors in the shape of at least two Hoopoes, continental breeders that have overshot their breeding grounds off the back of southerly winds. They won’t linger, however, and will soon reorientate to return south. One of the most fascinating aspects of the unfolding migration has been the return of the Cuckoos, fitted with satellite tags by the BTO. Regular updates on their progress continue to appear on the BTO website (www.bto.org/cuckoos). The five tagged last summer, were all captured in East Anglia and it will be interesting to see if they return to the same sites.

The pattern of activity seen in our birds has been mirrored in the county’s butterflies, with a good number of early reports of species that overwinter in the adult form, followed by several lean weeks in which few sightings were forthcoming. Other species are now being reported on the wing, including Orange Tip and Holly Blue, so it does feel as if the butterfly season is now properly underway. Other insects have been taking advantage of early season nectar, with good numbers of bumblebees foraging in my garden and quite a number of hoverflies as well. The changeable weather that we see at this time of the year does deliver something of a stop-start feel and while it can appear that spring is here to stay one morning, the next can suggest a return to winter. It is a great time of the year to be out and about though as each new sighting delivers a thrill.

Stoat

Normally alert to human approach, the Stoat must have been unaware of me as I skirted the edge of the Rabbit warren that is a bustle of activity at this time of the year. It was not until I was within just a few feet that the Stoat dived for cover, leaving me to settle and wait in case its inquisitive nature afforded me with a second, more prolonged viewing. At this time of the year Rabbits dominate Stoat diet, with male Stoats in particular targeting them, while females tend to take more small mammals, like mice and voles.

Prey preferences reflect the size difference that exists between male and female Stoats; males are the larger of the two sexes and, at about 30cm in length, this one was undoubtedly a male. This makes males better equipped to deal with larger prey, like Rabbits, although both sexes will tackle prey species that are decidedly larger than themselves.

A dominant male Stoat will hold a territory that overlaps with several (smaller) female territories and during the breeding season he may expand the size of this by up to fifty-fold. During this period, which peaks between April and June, he will seek out the females, spending a few days with each, before moving on to find another. Female Stoats use delayed implantation of the fertilized egg, meaning that young are not born until the following Spring.

Sometimes when I am out and about I get the opportunity to watch a Stoat hunting, as it moves through an area and searches burrows and other forms of cover within which potential prey may be found. From time to time, a Stoat will stand on its hind legs, a behaviour known as periscoping, presumably to get a better view of the surroundings. I have also witnessed encounters where a Stoat has taken a Rabbit, sometimes with a quick charge but other times seemingly able to mesmerise its prey. Some individuals may be seen to exhibit a wild, cavorting dance, but whether this is a behaviour used to mesmerise prey or the result of an infection of a nematode worm is unclear. This particularly unpleasant parasite is thought to occur in up to a third of British Stoats, infesting the sinuses and bringing about skull deformity and, presumably, other internal damage.

This Stoat was showing no signs of emerging from the cover into which it had dived and I attempted to imitate the squeaking and squealing of an injured Rabbit. This sometimes brings them out into the open, a trick that an old gamekeeper friend once taught me. Either the Stoat was not playing ball or, more likely, my squealing Rabbit impression was not up to scratch.

A tree-nesting goose

It was the raucous calls of the male Egyptian Goose that led me to suspect that the female was nearby and it was not long before I spotted her, crouched in the entrance of a tree cavity. It looked as if the female had been about to leave the cavity in which her nest was placed to take a break from incubation and grab some food. I moved away and took up a position further along the river, one that allowed me to watch back from a distance, the geese undisturbed. The female soon joined the male and the two crossed the river to feed on the short turf of a nearby paddock. I did not have time to hang about and watch her return to the nest, but now that I knew where it was I could come back another day.

Although Egyptian Geese may nest on the ground, they are more commonly found nesting in large tree cavities, such as this one in the broken limb of a mature Horse Chestnut. The limb protruded above the river, occupying a position above a particularly deep section on a bend. Monitoring this nest was not going to prove easy – boat and ladder looking likely.

Somewhere within what appeared to be a significant cavity, there would be a pile of grey down, with a few white underbody feathers mixed in, and up to a dozen large, creamy white eggs. The female could spend up to a month incubating these, beginning her task once the last egg had been laid and the clutch completed, and soon after hatching the young would leave the nest. As with all tree-nesting ducks and geese, the young have to jump from the nest and so face a daunting descent onto water or, more usually, hard ground. It is a wonder that they do not injure themselves as they fall to earth. At least these goslings would only have an eight-foot leap into the water that lay below.

The Egyptian Goose is a familiar enough within the county but it is worth remembering that this is a non-native species, introduced from South Africa. The East Anglian population is well-established and self-sustaining, the breeding range now expanding into central and southern England. Unlike several other introduced wildfowl, the Egyptian Goose population has been slow to expand. One of the reasons for this may be that it nests so early in the year and the resulting young retain their down for well over a month, something that leaves them susceptible to the chill of late winter hard weather. Additionally, it is a highly territorial species, breeding at low density and limited by the availability of suitable nest sites.

A forest dawn

The timing of dawn means that I now get out to the forest almost bang on first light and I relish these early spring mornings for the wildlife watching opportunities that they deliver. It is, in my mind, the best time of the day and, quite possibly, the best time of the year.

There is still a chill in the air as I head out. Sometimes a slight frost will crisp the vegetation but on other mornings the air will be heavy with moisture, the vegetation dripping and the dogs soon soaked. Two Roe Deer that have been hanging around this block of forest are present again this morning, cautiously watchful but tolerant of my regular presence. Less often these days I catch a glimpse of a group of Red Deer and rarer still is the sighting of one or more Fallow Deer. Interestingly, the numbers of Muntjac are much reduced and instead of seeing several each day I now only see perhaps one a week.

This morning it is the nonchalant ease of a fox that catches my attention. The fox is sitting some 70 metres or so ahead of me, just on the edge of the forest track, its upright posture alert but seemingly unconcerned. I halt and call the dogs to heel and for a few moments we watch each other. The sun is high enough and strong enough to cast long shadows, one of which cuts across the fox so that it appears two-tone, warm red across the head and shoulder and deep brown below. The fox relaxes, has a good scratch and then turns, trotting away into the undergrowth. It is a magical but all too brief moment and the best view I have had of a fox here for many months. We continue with our walk and pass the spot where the fox had been sat. As is the case most mornings there is the scent of fox on the air, something that the dogs invariably notice and they scout about before being called onwards.

Fox populations have struggled in a rural county like ours because of their reputation as vermin – unwelcome predators of game and domestic poultry. Such persecution has made them shy and, excepting the brazen individuals that make a living in urban Norwich, they are easily overlooked. As one of our larger mammals they should have a special place in our countryside, affording the opportunity for a wonderful encounter and providing children and adults alike with a special moment interacting with nature. We used to have foxes visit our garden when I was a child and I can still recall the sense of wonder that seeing such a creature had on me.

Norwich goes batty for bats

From time to time I will see or hear a bat flitting across my urban garden – I can still just about pick up the pitch of their echolocation calls. I definitely have Brown-longed Eared Bats visiting because I see them sometimes, perched on the wall of the passageway that runs under the upper floor of the house. They seem to like this sheltered spot and use it as a place to dismember some of the larger moths that they catch. Come morning, there is often a pile of discarded moth wings on the floor of the passage, and a sprinkling of bat droppings stuck to the rough wall.

Brown Long-eared Bats forage using two different strategies. As well as capturing prey during flight, as is the case in most other bats, they also take prey from vegetation, a behaviour known as foliage gleaning. This underlines an association with well-vegetated habitats – across much of its European range the Brown Long-eared Bat is a woodland or forest species. In Britain, however, there is a strong association with buildings, the species favouring them for its summer roosts, and so it is not unsurprising that they should be found hunting within an urban setting. I suspect that my garden is used because it is a part of a larger block of urban green space, complete with some mature trees and much shrubby cover.

There is much to learn about urban bat communities and this is one reason why Dr Stuart Newson and Norwich Bat Group have launched a new study. Called The Big Norwich Bat Project, the study aims to carry out bat surveys across the whole of the city and its surrounding area. The team are using cutting-edge devices that monitor bat activity throughout the night by recording the echolocation calls of any bat that happens to pass within range. The recordings are then downloaded and analysed by running them through computer programs; these compare the calls heard with a library of calls for which the identity of the species is already known. This approach has already made a significant contribution to our understanding of the distribution of bats elsewhere within the county.

The team aim to deploy a device in each 1-km square within their study area and are still looking to fill some gaps in their coverage. Take a look at their website (www.norwichbatgroup.org.uk/project.html) to see if your garden could be used to plug a gap. If the project proves successful then maybe the approach can be extended to cover other urban areas within the county. I’d certainly like to know what other bat species might happen to be using my garden when I am tucked up in bed asleep.

Ravens

The other day, a trip to Bristol to meet up with the BBC SpringWatch Team delivered an unexpected surprise in the form of a pair of urban Ravens. We had hoped that we might see an urban Peregrine, as the city now supports several pairs, but proved to be disappointed by the lack of birds at a regular haunt. Of course, the Ravens more than made up for this as they are a still a rare visitor to Norfolk and to see them in an urban setting was totally unexpected.

The return of the Raven to our urban centres comes after a gap of many centuries and reflects a broader recovery of its breeding population. Up until the end of the nineteenth century you would have been able to find Ravens breeding in just about every English county, but the ongoing persecution soon saw the species lost from most of its former breeding range. Ravens are scavengers for the most part, taking carrion or foraging among the refuse of our society. They also take a surprisingly large amount of plant material, including cereal grains, berries and even grasses, together with invertebrates, small mammals and small birds. It is the preference for carrion, especially that associated with livestock, that has contributed to their persecution over the years but a more enlightened attitude has aided their recovery.

It is the western strongholds that have driven the recovery, the population expanding slowly but steadily eastwards into southern and central England. Established pairs tend to remain within their breeding territories throughout the year but young birds undertake larger movements and it is these individuals that have colonised new areas. Some of these dispersive movements can be substantial as highlighted by the recovery of a juvenile Raven at West Stow (just over the border into Suffolk) back in 1988; this individual had been ringed as a chick the previous summer in Ireland. Breeding pairs are now established in Sussex and Kent and to the north of London, but the species is still some way off re-establishing itself in East Anglia.

Bristol it seems, now has an interesting mix of larger birds. In addition to the Peregrines and Ravens, there is a sizeable population of inland-breeding gulls, dominated by Herring Gull and Lesser Black-backed Gull. For me it is the Ravens that steal the show. The sheer size of these birds – we were lucky enough to see them alongside a Carrion Crow, which they dwarfed – and the wonderful croaking call, deliver a powerful sense of character. With luck, we will see them return to Norwich one day, our attention caught by a croaking call and an upward glance will reveal the silhouette of this striking bird.