Mammals – Page 5 – Hoopoe

NHBS In the Field – Echo Meter Touch 2

First released in 2017, the Echo Meter Touch 2 (EMT2) and Echo Meter Touch 2 Pro (EMT2 Pro) from Wildlife Acoustics are highly popular bat detectors for naturalists and professionals alike. By plugging the units directly into your phone or tablet, your device is transformed into a fully functional, full spectrum bat detector. The free Echo Meter app (available on the App Store and Google Play Store) allows the user to watch live, real-time sonograms as bats pass above.

The EMT2 Pro can be purchased as either an iOS model (with a lightning connector) or an Android model (with a USB-C connector), but the EMT2 is now only available as an Android model. We highly recommended checking the list of compatible devices on the Wildlife Acoustics website before purchasing your EMT2 (see compatibility of phones and tablets here for Android). This list is not exhaustive and is continually updated as further models are tested.

When using in conjunction with an Android device with a USB-C connector, an adapter will be required. As of 2021 these are now included for free with all Android Echo Meters, an addition we are sure will be greatly appreciated by customers going forward.

The EMT2 Pro is very similar to its counterpart, however additional features and a higher quality microphone make this option more suitable for professional ecological surveys and acoustic analysis. Adjustable gain (Low -12dB, Medium or High +12dB) is one particularly helpful addition. For a full break down of the differences between the EMT2 and the EMT2 Pro please see Wildlife Acoustics’ comparison page.

We plan to further test and compare the EMT2 and EMT2 Pro for a future post. On this occasion we only tested the EMT2 – but the set up and use is fundamentally similar for both models.

How we tested

During August 2020 we took several EMT2 units to a nearby woodland to survey for the presence of bats. The Android units were used in conjunction with a Samsung Galaxy Tab S3 (requiring the micro USB to USB-C adapter) and the iOS units used with an iPhone SE 2020.

The EMT2 is incredibly lightweight and small, weighing just 20g and measuring 48 x 35mm. Supplied in a small pouch, the detector is perfectly pocket-sized. For peace of mind, we connected a keychain to the pouch to keep it safely clipped to the inside of our bag.

Set-up was incredibly easy; we simply downloaded the free application, plugged in the device and immediately began recording. It is worth noting that, when plugging the EMT2 into the phones without an adapter, the phone cases had to be removed in order to allow proper connection.

We made sure that the Trigger Minimum Frequency was set to 12kHz, the level recommended by Wildlife Acoustics in order to stop noise recordings while not missing any species of bat. On the ‘Auto ID Selection’ tab, we chose the correct region and country allowing the impressive auto-ID feature for UK bat species to be enabled (see video below on how to change these settings).

The EMT2 then automatically recorded any bat activity detected above 12kHz and applied a suggested species identification based on the waveform and frequency. The app offers several ways to share these recordings, but we chose to directly plug our phones/tablets into a computer to transfer the files directly.

What we found

The Echo Meter is incredibly intuitive and easy to use, so certainly suitable for beginners and professionals alike. Any questions or issues can easily be resolved via the User Manual, found under the Information tab on the app and offered in English, French and German. Personally, we preferred this digital option rather than having to flick through a paper copy during a dark evening survey. However, copies of the user manuals can be found here, for those who would prefer to print a hard copy.

The on-screen live sonograms were particularly impressive and allow surveyors to get an idea of the potential species present while still in the field. While waiting for the bats to emerge, we enjoyed watching the calls of birds and crickets (see our blog post here on monitoring Orthoptera using bat detectors) – an unexpected advantage of the EMT2. It is certainly understandable why the EMT2 is so often used for community engagement at bat walks and BioBlitzs around the country.

We found that, for the species common in our area, such as Common Pipistrelle (Pipistrellus pipistrellus), Soprano Pipistrelle (Pipistrellus pygmaeus) and the Noctule (Nyctalus noctule), the auto-ID feature appeared mostly accurate. Although, on one occasion before dusk we found that a bird call triggered a Common Pipistrelle identification. It is important to note that no Auto-ID feature can be 100% accurate, and Wildlife Acoustics make it clear that users should always manually verify the identification.

The automatic triggered recording worked very smoothly and did not appear to miss any bat activity. Despite this, it was reassuring to know if we noticed something we wanted to record, we also had the option to manually trigger recording – another feature that would be useful if wanting to listen to non-bat species. Each recording was GPS tagged, a neat feature that tracked our transect throughout the evening. When sorting through recordings, the option to sort by species was helpful to move noise and ‘No ID’ audio clips.

The only limitation we found with the EMT2 is how quickly our batteries drained. This is of course not a fault with the EMT2 itself and is to be expected with continual recording, but it is worth considering your phone or tablet’s battery life may impact your use of this detector.

Overall, the Echo Meter Touch 2 is a fantastic detector that is very affordably priced for the number of features it offers. The free app is continuously updated, and newly developed species classifiers added.

Common Pipistrelle (left) and Soprano Pipistrelle (right) recorded and identified on the Echo Meter app.

The Echo Meter Touch 2 and Echo Meter Touch 2 Pro are available from the NHBS website.

Visit nhbs.com to view our full range of bat detectors. If you have any questions about our range or would like some advice on the right product for you, then please contact us via email at customer.services@nhbs.com or phone on 01803 865913.

Winter Hibernation

What is hibernation?

During the winter months, cold temperatures and a lack of food can make survival challenging for many species. Some animals, particularly birds, solve this problem by migrating to a warmer location where food is more plentiful. Other animals utilise a different solution and enter a period of torpor or hibernation as a way of conserving energy throughout this time.

During hibernation, the animal will slow their heart rate and breathing while at the same time lowering their metabolism and body temperature, all of which vastly reduce the amount of energy they require. Throughout the hibernation period, the animal may become active again briefly, either for a bathroom break, to eat some food, or if the temperature becomes too low for them to survive without moving. As preparation for a period of hibernation, as much food as possible will be consumed and a suitable refuge or hibernacula found (or built).

Which animals hibernate in the UK?

Dormice, along with bats and hedgehogs, spend the winter months in hibernation. Image by Bruce Detorres via Flickr.

Mammals

Although many small mammals, including mice, shrews, badgers and rabbits, enter short periods of torpor throughout the winter, the only mammals in the UK that truly hibernate are bats, dormice and hedgehogs. Bats utilise hollow trees, roof spaces, caves and bat boxes and will usually spend the entire winter, from November to April, in hibernation. Dormice choose the seemingly riskier solution of making a nest using natural items such as logs and leaves on the floor of forests and woodland. Hedgehogs build hibernacula using dead leaves, twigs, log stacks and compost heaps and, although evidence shows that they rouse several times during their hibernation, they rarely leave these nests. The only exception to this is when the temperature drops too low – at this point they may depart their existing nest and build a completely new one with better insulation! In general, hedgehogs hibernate from November to April, but depending on the temperature and weather, this can vary from year to year.

Reptiles and Amphibians

All reptiles in the UK hibernate. Typically this will begin in October in response to reduced daytime temperature and shorter day length, but it can vary depending on the year and species. In general reptiles will use dry and sheltered spots, often utilising tree roots, abandoned animal burrows or compost heaps.

All species of amphibian in the UK also hibernate, although not all individuals will do so on any given year. In mild winters newts may simply enter a state of low activity rather than complete hibernation. Most amphibians will choose a quiet location in the soil, a compost heap or rockery, or even a garden shed to spend their hibernation. A small number of frogs, however, will hibernate at the bottom of a pond.

Insects

Bumblebee colonies die off in the autumn with only the new queens surviving. To make it through the winter, these queens burrow into the soil where they are protected from the cold and weather for up to nine months! Honey bees use a different strategy and do not hibernate as such – instead they survive as a reduced-size colony which huddles together with the queen at the centre. The bees rotate their positions so that each takes its turn on the outside where the temperature is lowest.

Most butterflies spend the winter in larval form. Several species however, including Brimstone, Peacock and Comma will hibernate as adults, using either vegetation such as bramble and ivy, or outdoor structures such as garden sheds and barns.

Ladybirds survive the cold winter by hibernating in rotting logs, under leaf litter or even inside houses. They like to hibernate in colonies, often forming groups containing thousands of individuals.

Ladybirds emerging from hibernation. Image by Dr. Mary Gillham Archive Project via Flickr.

Climate change and hibernation

Most animals that hibernate rely on a combination of cues such as day length and temperature to know when it is the right time. As climate change continues to affect local and global temperatures and weather patterns, many animals are hibernating later in the year and becoming active again earlier in the spring, as temperatures during the winter are now often much warmer. Hibernating for a shorter period can put pressure on food availability and can cause a mismatch in the timing when animals require a resource and when that resource is available. For example, bees emerging from hibernation require a ready supply of nectar. If they emerge earlier than usual however, before flowering season, this food source may not be available to them.

Always make sure to check your bonfire for hibernating animals! Image by Ian Carroll via Flickr.

How can I help hibernating animals?

• Leaving some areas of your garden that are untidy and overgrown will provide plenty of space for animals to hibernate over the winter. Piles of logs, long grass and compost heaps all provide safe places for animals such as snakes, hedgehogs and other small mammals.

• If you’re celebrating bonfire night, don’t forget to check the bonfire for hibernating animals before you light it – particularly if you have built the structure several days or weeks before the big night.

• Providing artificial hibernacula in your garden, such as a bat box, hedgehog house, or insect box, will help to provide suitable hibernation spots for these species.

• If you find a butterfly that has chosen to hibernate inside your house, it’s best to gently relocate it to an unheated building outside, such as a shed or garage. (Central heating is extremely damaging to a hibernating butterfly and will desiccate their delicate wings and bodies).

• Don’t forget those animals that don’t hibernate over winter. Birds in particular will benefit from a variety of foods such as peanuts, mealworms, fat balls and seed.

The Acoustic Identification of Small Mammals

As static bat detectors have become more widely used, there are now many thousands of hours’ worth of nocturnal recordings captured each year from a vast spread of locations. This level of coverage has not only improved our ability to monitor bat populations, but also offers the potential to gather information on other animals that communicate at the same ultrasonic frequencies as bats. The calls of bush-crickets, for example, are commonly picked up as ‘by-catch’ during bat surveys, which has allowed the development of software that automatically recognises any cricket calls in a recording and assigns them to individual species.

In the December issue of British Wildlife, Stuart Newson, Neil Middleton and Huma Pearce explore the previously untapped potential of acoustics for the survey of small terrestrial mammals – rats, mice, voles, dormice and shrews. Small mammals use their calls for a variety of purposes, including courtship, aggressive encounters with rivals and communication between parents and their offspring. To the human ear, the high-pitched squeaks of different species sound much alike, but closer examination reveals them to be highly complex, extending beyond the range of our hearing into the ultrasonic and showing great variation in structure.

Mammal terrariums used for holding individuals overnight in the recording ‘studio’.

But is it possible to distinguish the calls of different species? To answer this question, the authors began the time-consuming task of building a call library by taking recordings of all Britain’s native (and some non-native) small mammals. Call-analysis software was then used to examine the recordings and look for consistent differences between species, with some fascinating results – the calls of shrews, for example, can be readily separated from those of rodents by their warbling/twittering quality, while the house mouse typically calls at a higher frequency than any other species. Remarkably, it appears overall that the vocalisations of most species have their own diagnostic features, and that, with care, it should be possible to identify a high proportion of calls to species level.

Recorded calls of (a) Brown & (b) Black Rats

Small mammals are unobtrusive and hard to observe, which means that even the more familiar species, such as the Brown Rat, are severely under-recorded. The ability to detect and identify small mammals by their calls therefore offers great potential to help fill gaps in our knowledge of the distribution and abundance of British species. Analysis of calls collected by static detectors – whether specifically set to target small mammals or deployed as part of a bat survey – could in future offer a rich source of data and help to complement traditional methods, such as the use of Longworth traps or footprint tunnels.

To read about the key identification features of small-mammal calls, see the December issue of British Wildlife (more information can be found on the British Wildlife website) and to accompany this article, audio clips of the species discussed are available to download here. This work will contribute to the BTO Acoustic Pipeline, which allows the upload of sound recordings and automatically detects and identifies any calls of bats, bush-crickets and small mammals. For more information about the project, see the BTO Acoustic Pipeline webpage and read comments from the authors here.

Bat detectors for small mammal survey:

Passive bat detectors are designed to be left in the field for unattended monitoring and are the ideal choice for ecologists and researchers wishing to monitor local bat populations. For similar reasons, they are also a good choice for recording small mammals as they record all frequencies continuously and retain complex details of the call structure, allowing the sounds to be analysed later using bioacoustics software. Detectors such as the Song Meter Mini, Anabat Swift and Elekon Batlogger A+ all features excellent weatherproofing, long battery life and the ability to programme recording schedules.

Song Meter Mini
#248177

Anabat Swift
#236256

Elekon Batlogger A+
#228313

NHBS In the Field – Mammal Footprint Tunnel

Footprint tunnels are a useful, cost-effective, non-invasive tool for presence/absence surveying of small mammals. Food left in the centre of the tunnel encourages passing animals to walk over the ink pads, leaving their footprints on the tracking paper. With the use of a guide, the mammal in question can then be identified from the footprints left behind.

There are a number of benefits of using footprint tunnels. As they are non-invasive, the tunnel can be set up and left without fear of harming animals and are a good way to assess a site prior to in-depth species studies. They are also quick to check compared to other methods. For example, although camera traps are also useful for presence/absence studies, it can be time consuming to sift through captured images and videos.

As is useful for any piece of equipment, footprint tunnels (and their replacement materials) are very light (55g), and so are easy to take out into the field. However, as they are quite long (119.5cm) they can be cumbersome to transport. Despite this, transportation is made easier due to their ability to be flat packed – their plastic construction allows for them to be folded easily.

The NHBS Mammal Footprint Tunnel comes flat packed with helpful assembly instructions. When assembled, the tunnel is wide enough to fit a full sheet of A4, saving you the trouble of cutting paper to size to use in the tunnel, and is large enough to allow access to animals such as hedgehogs but not larger mammals, such as foxes or badgers.

In addition to the kit you will need eight paperclips per trap, masking tape, some vegetable oil to mix with the included charcoal to make the ink, and some bait (chopped unsalted peanuts or dog/cat food is recommended).

Our work building is situated alongside the river Dart, only separated from the riverbank by a small wall and we wanted to find out what mammal species we have in the vicinity of our building. So we field tested a single NHBS Mammal Footprint Tunnel and here we share what we found and our thoughts on the tunnel.

How We Tested

The above image shows the kit contents: to the left is the tracking plate and on the right is the flattened prism that forms the tunnel. In the top right corner are the pins that secure the tunnel to the ground, charcoal, paper and masking tape (please note, paper, masking tape and vegetable oil are not included in the kit).

To set up the tracking plate, a sheet of A4 paper is placed at each end and secured with tape (ordinarily the paper would be secured with paper clips as is suggested in the instructions). Then we put several strips of masking tape across the centre of the tracking plate to create a large area of tape. The ink (a mixture of charcoal and oil) was painted on the two grey strips across the centre and bait was placed in the central area between the two ink pads.

Pictured is the tracking plate with the paper and masking tape attached.

We first set up the trap next to a bird feeding station – we already knew that the feeder is visited by voles and squirrels, and so would be an ideal place for us to put the footprint tunnel to the test! Although the feeder is raised, we opted to put the tunnel on the floor so that it was accessible to small mammals. As the tunnel was not placed on soft ground, bricks were used to secure the tunnel in place rather than the metal pins included in the kit. For bait we used bird seed as this is what the animals are used to eating at this particular location. The trap was left here for one (wet) night.

The first location that the tunnel was set was next to a bird feeder known to be visited by squirrels and voles.

The first tunnel set up, secured by bricks.

The second set up was just outside of our office alongside the wall that bordered the river. We hoped that this area would be patrolled by a number of small mammals, particularly hedgehogs as they have been seen here before. We baited the tunnel with cat food and the trap was left for three nights over the weekend – being outside office hours, we hoped disturbance would be minimal during this time.

The second placement of the tunnel

What We Found

The inner tracking plate was slightly fiddly to insert into the assembled prism tunnel, and we found that it was much easier to assemble the (pre-bent) prism round the tracking plate rather than sliding the tracking plate in. We used masking tape to secure the paper rather than paper clips as is suggested; this was beneficial when trying to get the tracking plate inside the tunnel as it was more secure than using paper clips.

In order for the bait to stay in place in the centre of the tracking plate the bait needed to be inserted after the tunnel was assembled. And so, because of the length of the tunnel, placing the bait into the tunnel was a little awkward. We found using a trowel to insert the bait made access easier, especially when trying not to disturb the ink.

In the first set up we were pleased to see that a vole had visited our tunnel and that the recording paper had stayed relatively dry despite the very wet weather. Sadly for our second attempt our bait of cat food was eaten by a cat!

Vole footprint tracks from first sighting. The photo is taken to scale of an A4 paper (the page filled the photo).

Our Opinion

The Mammal Footprint Tunnel is an easy-to-use, lightweight monitoring device and a great tool for many small mammal presence/absence studies. Due to its simplicity and low cost, it is ideal for students or for those involved in public engagement.

Despite its light weight, its size makes it a bit of an awkward shape to carry, both when assembled and when flat packed. However, its ability to be flat packed allows for multiple tunnels to be transported without any additional difficulties. Placing ink on the outer edges of the paper may result in more footprints- in our experience something seemed to enjoy munching on the paper before getting to the actual bait. Getting the ink to the right consistency takes some trial and error, but we would recommend using less oil to achieve a thicker ink so that any footprints left behind are as dark as possible so that they are easier to identify.

The pins were sufficient in securing the tunnel and saved it from being blown away by the wind, but a medium-sized mammal (a cat in our case!) could move the trap when secured in soft soil, so this is something to bear in mind when situating your trap.

Overall this is a very easy-to-use, affordable tool and we would highly recommend it as an effective presence/absence surveying method for small mammals.

The Mammal Footprint Tunnel is available through the NHBS website.

To view our full range of mammal surveying equipment, visit nhbs.com. If you have any questions about our range or would like some advice on the right product for you then please contact us via email at customer.services@nhbs.com or phone on 01803 865913.

NHBS In the Field – Pettersson U-series USB Ultrasonic Microphone

The Pettersson U-series microphone is a powerful ultrasonic USB microphone that is designed to be plugged into a smartphone, tablet or laptop to listen to and record bats. The microphone is available in two options: the u256, which has a sample rate of up to 256kHz and the u384, which has a sample rate of up to 384kHz. Both models use a MEMS ultrasonic microphone for its high sensitivity, low noise and ultra-low power consumption. The units themselves are pocket sized and feature a robust aluminium outer casing, making them ideal for taking out into the field. They connect to your device using a micro-USB connector but can be converted to connect to USB-C, lightning connector, or USB by using an adapter. Once connected, they can then be used alongside a variety of apps for viewing and recording bat calls.