An early feast

Today, whilst out birding, something caught my eye. I have started visiting Warwick Racecourse more often this past year, mainly to build up a species list for the site and to get some nice photographs of different birds. 

At this time of year, I am usually focused on the Skylarks and the returning warblers; however, today, what caught my eye first was a flock of Starlings. Starlings are not unusual on site. They are present all year round in small flocks, usually on the short turf by the football ground. Here they potter over the grass, looking for insects and probing for leatherjackets. Today, however, they were further over near the water channel. They sat along the fence line, some of them shooting into the air, hovering and then returning to the fence. If I couldn’t see directly that they were Starlings, I would have identified them as stocky flycatchers, twitching into the air, fluttering and returning to a perch. It was this odd behaviour and that thought of the flycatcher that held the answer. 

Taking a moment to look around me, I noticed that the air was filled with black flies. Flies are often a very overlooked taxon, unless they are flying around your food, but they are incredibly important ecologically. The flies I could see were familiar to me. 

They were jet black, some about an inch long. They floated in the air with their legs dangling, looking like some kind of drone. They seemed to bob on the air currents, settling occasionally on vegetation. These flies are known as St. Mark's Flies (Bibio marci) or the hawthorn fly. They are called St Mark’s flies because their emergence flight period usually coincides with St Mark’s saint day (25th April). 

Image from Warren Photography - https://www.warrenphotographic.co.uk/28027-st-marks-fly-in-flight

The fly is known for its spring appearance. Its larvae live in the soil, feeding on roots and decaying vegetation before pupating into their adult forms, which then take to the air, slowly drifting in swarms with their legs hanging down. This stage is short-lived, lasting perhaps a week as they search out a mate. During this week, they sustain themselves by feeding on the nectar of fruit trees and hawthorn flowers, making them important pollinators for these species. 

In many ways, this display of floating dancing flies is a terrestrial form of that exhibited by Mayflies over our rivers. These swarms form an important food source for many species. The Starlings had identified this and left their usual spot to take advantage of the glut of food.

It's one of nature's miracles, the ability of such tiny organisms to synchronise and emerge together. Sometimes it's the small things that reveal the most.

An upgraded Mostela

 

I have embraced camera trapping as a medium for observing and recording nature. What started as a whimsical addition to my arsenal of ecological tools has turned into a passion. I have been running cameras for over 10 years, have experimented with several techniques, and have even published a book on the topic.

One of the most interesting tools in camera trapping is the Mostela. I have blogged about this device before. Mostelas are designed to improve the detectability of small mustelids such as Stoats and Weasels.

Mostela as detailed by the Vincent Wildlife Trust 2022 (image courtesy of Vincent Wildlife Trust)

They are essentially a box with a drain pipe entrance that contains a camera. They can be baited or unbaited. The theory is that these spaces will be used by small mammals such as voles, mice and shrews; they will visit the site for food if baited or just investigate it. Their continued presence creates a scent trail that Weasels and Stoats will follow when hunting.

Weasel recorded in the current fixed Mostela in 2025

Raw Components

In reality, I have had little success with capturing images of Weasels and Stoats. I am not entirely sure Stoats are resident on the site, in person or on camera. Stoats have only been recorded once since 2015. Weasels, however, are resident, but due to their speed, they are not easily detected on camera. On Otter Cam and the mostelas, they have been recorded once a year, whilst the hedgerow camera recorded them on average twice a year.

The greatest benefit I have found is not in collecting mustelid data but in observing the small mammals. Small mammals can be recorded with standard camera placement, but better identification is achieved with small-mammal rigs and mostelas.

I have used home-built mostelas for over two years, as well as purpose-built ones purchased from the Netherlands (An expensive approach!), and now feel like I want to experiment with the design.

Assembled

One drawback of the mostelas is that, during the daytime, the closed chamber makes it still very dark and often requires infrared to make any visitors visible, making the visitor's pelage colour hard to see. This can be important in identification. To counter this, I am experimenting with a translucent lid that should give better colour clarity during the day.

I have also removed the base plate to reduce costs, provide a more natural view, and allow the camera to be placed more effectively. Often, the best camera positioning involves tilting the camera down. With Gardepro and Bushnell cameras, which are my preferred brands, the lens is often quite high on the device, meaning that individuals moving closer to the camera are often missed or hard to see. Without a base, it is possible to dig a trench for the camera to sit in.

To build this mostela, I have used marineplywood that I bought online pre-cut to size. For the entrance tubing I am experimenting with two entrances opposite to each other using bend fixtures bought from Amazon. This cuts down on the difficulty of cutting and sealing a length of drain pipe.

I have tested the principles in the back garden but this weekend I will install it in the wild to replace my existing mostelas that is slowly disintegrating.

58 and counting

 

Today is day 88 of the year; over the last 88 days, I have seen 58 different bird species.  Just over halfway through this year's attempt to complete the Warwick 100. This is the local attempt for local birdwatchers to see 100 different species over the course of a year. I decided back in January to keep a species list and track the number of species I recorded week by week.

This graph shows the week-by-week increase in species, essentially a Species Richness curve.

The most interesting species seen so far have been:

Northern Shoveler

Mandarin Duck

Gadwall

Oystercatcher

As part of this effort, I spent last weekend scouring Warwick.  On  the Friday, I visited the Chase Lakes, the Hopyards, St Nicholas Park and finally the flash at the Saxon Mill travelling along 5 Km of the River Avon. On Saturday, I visited the Racecourse, and on Sunday, I went to my normal patch. 

In total, over the 4 hours of survey time, I recorded 46 species. This shows how quickly a species list can be built up over a relatively short period. The key is to visit as many different types of habitats as possible. We are lucky in Warwick to have woodland, farmland, grassland, rivers, lakes, and reedbeds.58

Ups and Downs for Raptors

 Birds of prey, as apex predators, are often used as indicators of ecosystem health. Their fortunes reflect changes lower down the food chain and can help us understand how other species are responding to wider environmental pressures.

 I have accumulated enough data over the years to begin exploring these dynamics more meaningfully. So, when I recently found myself musing that I seem to be seeing Peregrines far more often than I used to, I dug a little deeper and put that feeling into context. That thought was really the combination of two separate observations: first, a Peregrine perched on Guy’s Cliffe House, and secondly, how rare it has become for me to see Kestrels at all.

Peregrine

Raptors have had mixed fortunes in the UK, and their numbers have changed drastically within my lifetime. As a child, seeing a Buzzard in Warwickshire was a rarity; now they are ubiquitous, and it is the Red Kite that still feels like a novelty. Kestrels were once abundant; no car journey felt complete without spotting one of these wind-hoverers over the motorway. As for Peregrines, those required a special trip to places like Symonds Yat. Thirty years have passed since my childhood, so what does my local patch tell me about raptors and how they have changed?

After watching the Peregrine perched on the house for a while, I returned home and looked back over the data I’ve collected. I keep a master database spreadsheet that tracks frequency, numbers, and abundance for all bird species recorded. When comparing species, I use a relative abundance measure that weights sightings by the time spent in the field. This helps account for extraneous factors that can otherwise skew results. I plotted these values as a graph and added some contextual information.

 I chose to look at all raptor species that have occurred on my site since 2004. Owls were excluded because my survey methodology substantially underestimates their numbers. When I first started recording, there were three main raptor species: Buzzard, Kestrel, and Sparrowhawk. This has since increased to five, with the addition of Red Kite and Peregrine.

 Buzzards have always been, and continue to be, the most abundant species. They are seen on practically every visit and, pleasingly, in 2024, they nested directly on the patch. Despite low rabbit numbers, their favoured prey, they continue to do well, raising two to three young locally. This mirrors the national picture, where Buzzards are now a stable and widespread species after expanding from their upland strongholds during the 1990s.

Sparrowhawk

 In contrast, Kestrels have undergone a serious decline over the same period and are now Amber-listed. The loss of rough grassland, agricultural intensification, and increased competition are all thought to be contributing factors. Locally, the decline was accelerated by a specific event. A tree in which a pair frequently nested was damaged when a winter storm in 2022 tore off the top of an Ash, exposing the nesting cavity. The loss of that single tree has had a noticeable effect on sightings. With low national numbers and no replacement pair moving in, the area has yet to be recolonised. Despite an abundant vole population in the meadow, I suspect this will remain the case for some time.

 Sparrowhawks are common across the site, as they are around the surrounding housing estates. They remain at a steady but relatively low abundance, which likely reflects their speed and ability to evade detection rather than true scarcity. As specialists adapted to hunting small birds on the wing, they face little competition from other raptors. Short-term peaks in the data likely reflect particularly successful breeding seasons rather than a long-term trend. National Breeding Bird Survey data suggest Sparrowhawk populations are broadly stable following their recovery from pesticide-driven declines in the mid-20th century.

Red Kite

 Pesticides such as DDT had perhaps their greatest impact on Peregrines, which came close to extinction in the 1960s. Their recovery stands as a flagship conservation success. Numbers have risen dramatically, and since the turn of the millennium, they have increasingly colonised urban and suburban sites. A local example is the nesting pair on Leamington Town Hall, which first bred in 2017 and have since raised more than 30 fledglings. My patch lies close enough to this site to be used regularly as a hunting ground, and many of this winter’s sightings appeared to involve an adult teaching a juvenile. Peregrines are territorial, so I don’t expect abundance to increase further — but wouldn’t it be something if they eventually nested in the ruins of Guy’s Cliffe House?

The final species of note is the Red Kite. I saw my first one when studying in Aberystwyth in the late 1990s, when the idea of them occurring in Warwickshire seemed laughable. Now they breed within the county and continue to increase in number. They first appeared locally in the early 2020s and are slowly becoming more regular, with the county still very much in the colonisation phase following reintroductions in Wales and the Chilterns. I hope breeding will occur closer to the site in future, though that will depend on factors such as nest-site availability and competition with Buzzards.

Buzzard and Kestrel

 So, what does all this say about raptors more generally? It’s clear that my small patch broadly mirrors regional and national trends. Generalist species like Buzzards and Red Kites appear better able to exploit our fragmented landscapes and varied food sources. It shows that when persecution pressure is lifted and sufficient nest sites are available, raptors can and do recover. At the same time, it highlights that some specialists continue to struggle. Sparrowhawks, despite their specialisation, seem to benefit from the widespread feeding of garden birds; here, there is nearly always an all-you-can-eat buffet somewhere nearby. Kestrels, by contrast, remain heavily reliant on rough grassland and vole populations, much as Buzzards once depended on rabbits.

My local story also illustrates how the loss of a single tree can significantly affect species abundance. In this case, the cause was weather rather than environmental vandalism, but it underlines how vulnerable populations can become once numbers fall. The takeaway is this: national recoveries are real but uneven; declines can be rapid and locally catastrophic; conservation often hinges on surprisingly small pieces of habitat; and patch-based recording matters. It really is the canary in the coal mine, and it contributes to the bigger picture.

When data can reveal a human truth

 

There are times when I review my data simply for pleasure. Not everyone would call that fun, but for me, there’s real satisfaction in looking back at the wildlife numbers I’ve gathered on my patch since I first began tracking them.

Whenever I revisit the dataset, my attention is immediately drawn to the gaps. Little voids that tease my more obsessive tendencies and make me wonder what stories were lost. The biggest gap was in 2018, when I collected no data for three months. A fallen tree trunk had crashed into the stanchion of the old stone bridge, forcing its closure for repairs. During that time, I couldn’t reach my patch. It felt strange and, frankly, unsettling to lose my weekly visits. Smaller gaps over the years come down to bad weather or illness, but the two-month gap in 2011 belongs to a darker chapter, a resurgence of my anxiety to a state where my focus was entirely on ensuring I could make it to work each day.

Table showing the average recording survey time on my patch

An important part of who I am, something I no longer hesitate to share, is that I have Generalised Anxiety Disorder. Thankfully, mental health no longer carries the stigma it once did, and I make sure the students I work with understand that these struggles can happen to anyone, and that a fulfilling life is still entirely possible. I won’t go into the details of what lies beneath my anxiety; therapy and introspection have given me clarity, but those details are for me alone. What matters is that I’ve come to accept that my anxiety is part of who I am. It doesn’t define me, but it has shaped my personality and my life in irreversible ways.

I had my first recognisable anxiety attack at 16, and a small breakdown in the final year of university. Strangely, my patch became part of my recovery. At its worst, my anxiety manifested as an odd mix of agoraphobia and claustrophobia, seemingly contradictory, yet somehow, I managed both at once. Sometimes they alternated; sometimes they arrived together, leaving me avoiding being indoors but unable to stray too far from home.

My visits to the patch began in 2002 as a way to keep my ecological skills sharp and to coax myself out of the house. I started simply walking around and taking in the air, but the scientist in me soon began making notes, casual observations at first, without a strict method. In 2004, as my love for the patch deepened, I established a clear protocol and began recording every species I encountered. By the end of 2025, I had visited the site 982 times, spending a total of 797.7 hours there, the equivalent of 33 full days immersed in nature.

Nature has always been a powerful healer for me and can be for many others. Time outside is actually prescribed now by doctors to treat stress and depression. Just 30 minutes in nature can lower cortisol levels, lift mood, and boost immunity.  My patch has carried me through sad and difficult times, and it helped me hold on to my sanity during COVID. I’ve grown enormously as an ecologist, coming to know so many species with an almost intimate familiarity. And yet, those gaps still catch my eye. I regret not being just a little stronger, not managing even a couple of visits during those hard moments. But the truth is: those gaps tell my story just as much as the data tells the stories of the birds and animals I record.

From Blue Tits to Great Tits: Rethinking bias in conservation

 It’s interesting how we often attribute distinct personalities to different bird species, drawing on stereotypes shaped by their appearance and behaviour. These impressions are rarely about individual birds, but rather about the collective image we form of a species. For example, Blue Tits and Great Tits are two of the most common birds I encounter, both frequent visitors to gardens and parks. Yet I realise I view these species through the lens of stereotypes, sometimes unfairly.

Stereotypes about birds are deeply ingrained in our culture, think of the elegance of swans, the wisdom of owls, or the ill fortune associated with magpies. In my own experience, I’ve always seen Blue Tits in a positive light, perceiving them as friendly and cheerful. Their small size and vibrant plumage give them an approachable air, and their chirruping calls seem engaging and pleasant. At the bird table, they flit about energetically, often appearing non-confrontational, and are often bullied by larger birds, especially their bigger relative, the Great Tit.

Great Tits, on the other hand, strike me as more assertive. Their stocky build and bold black markings remind me of a mask, almost like a burglar’s disguise. This impression is reinforced by their ability to mimic the calls of other species and their tendency to dominate at the bird table. I sometimes think of them as boastful, puffing out their chests and showing off their striking uniforms, perhaps the very model of a modern major general. Words like pride and conceit come to mind when I observe their behaviour.

However, I recognise that these descriptions reflect my own biases. The reality is more complex: Blue Tits can be aggressive towards smaller species such as Long-tailed Tits and Coal Tits, while Great Tits themselves may be bullied by Robins. Watch Great Tits for long enough, however, and you will find them as endearing as Blue Tits. They share many traits but fill very different niches. They are less flighty and more confident in their actions. Unlike Blue Tits, they will feed openly on the ground and will take to prominent treetops to sing. Thinking about Great Tits now, I realise they often herald the approach of my favourite season, spring. Their calls change subtly and become more strident.

Reflecting on these tendencies, I’m reminded of the importance of questioning our assumptions—not just about birds, but about all living things. By acknowledging our biases, we can strive for a more nuanced and accurate understanding of the natural world. It has long been a problem in nature conservation that it's far easier to raise money to save a species of cuddly animal like a bear or rodent than it is for a species of spider or snake. Some of our revulsion for certain species is biologically ingrained; we have an aversion to species less like us, bilateral species, those with radically different body shapes. The BBC ran an article on this back in 2012 and Green Earth explored it in 2024

Both articles describe the innate human bias that affects our efforts to defend biodiversity. This aligns with my growing sense that nature conservation should focus primarily on habitat protection and creation. We need to ensure ecosystems are stable and functioning and allow nature to take the lead. Species recovery will follow. I recall several Dormouse reintroductions in the early 2000s that failed because too much effort was placed on releasing individuals and boosting the local population before the habitat was repaired enough to support them. Of course, habitat protection is part of species reintroduction, and the lion's share of funding comes from species conservation, but we need to find an effective way to protect all species, regardless of their appearance or our own perceptions.

A Notter - When is an otter not an otter?

 Species identification can be a minefield, and one of the most common complications regards the differences between a mink and an otter.

In actual fact, once you have seen an otter, it is clear what it is, and the difference between it and a mink is pretty clear, but it is rare to see both together, and weather conditions can make things difficult.

Earlier this month otter cam recorded some great clips of both species, and I thought it would make a nice teachable moment.

Mink and Otters are both mustelids and exhibit similar body shapes. They are also both aquatic species and are found in similar habitats.

First of all, look at the video clip below:

It shows an animal emerging from water and then scouting around a little. It is definitely a mustelid, and aquatic. We can rule out Weasel due to its size and the lack of a white/cream chest and underside like a Stoat. Its back doesn't arch as much as a Polecat, and it's the wrong colour for a Pine Marten.

It's either a Mink or an Otter. What do you think?

What about the next clip?

This clip shows two animals running across the screen before entering the water. Look at the tail and muzzle.

Now that you have seen both species in the same location, you should be able to identify which is which.

Clip 1 shows a North American Mink, and Clip 2 shows a pair of Otters.

It's understandable to think that the individual in clip one is an otter. It is quite a large Mink and obviously a similar colouration to an otter, but note the following telltale signs.

The tail - Otter tails are much sleeker and rudderlike. They slim to a point, whereas Minks have broader tails that are a bit fluffier.

The head: Mink have thin heads that are taller than wide, but otters tend to be wider than tall. Eye placement is slightly different, with Mink eyes pointing more forward. 

Ears - Otter ears are much sleeker and do not stick out much from the line of the head, whereas Mink ears seem larger and are more noticeable.

Another key diagnostic feature is how they swim. Sadly, I do not have an image of mink swimming, but they do so in very different ways. Mink are only partially aquatic and not as well adapted. They tend to sit higher in the water and paddle quickly. Otters, when swimming, often only show their heads. They are highly evolved to swim; they are more agile and playful in the water. They use their tails to steer and propel, and will dive much more often.

Otter swimming

If you want to know more, then BBC Wildlife Magazine has a nice article here