Temperature Loggers Research Articles

Extracting past atmospheric warming and urban heating effects from borehole temperature profiles

Borehole temperature logs in urban areas often show deviation from the regional geothermal gradient that increases towards the land surface in the top ∼100m. This deviation is the sum of two effects: atmospheric global warming and urban heating. To invert the temperature profiles (T-logs), a novel analytical model is presented to distinguish effects of global warming and of urban structures on the ground thermal regime. The inversion is demonstrated on four characteristic T-logs measured in the city and suburbs of Zurich, Switzerland. The logging was performed in borehole heat exchanger U-tubes by an innovative, wireless measuring technique. Detailed information on past climatic and land use changes enabled the focus on two main urban heat sources, buildings and asphalt. For three of the locations, the T-logs could be reproduced with a plausible heating of the asphalt by 3–3.5°C, and an average temperature of 15–16°C below the basement of buildings. However, the other location within the highly urbanized area, is influenced by additional heat sources. In most of the cases, the increased subsurface temperatures and the associated stored additional geothermal energy, mainly originate from urban structures, while climate change is secondary.

Sitting in the sun: Nest microhabitat affects incubation temperatures in seabirds

During incubation parent birds are committed to a nest site and endure a range of ambient conditions while regulating egg temperatures. Using artificial eggs containing temperature loggers alongside ambient temperature (Ta) controls, incubation profiles were determined for four tropical seabird species at different nest site locations. Camera traps were used for ad-hoc behavioural incubation observations. Eggs experienced a range of temperatures during incubation and varied significantly between species and in some cases between different microhabitats within a species. Such variation has important consequences in the phenotypic expression of both physical and physiological traits of chicks, and ultimately species fitness. Exposed nest sites were more strongly correlated to Tas. Camera traps highlighted different incubation strategies employed by these species that could be related to trade-offs in predator defence, feeding habits, and temperature regulation of eggs. This study provides evidence that species with similar breeding habits could be affected by environmental stressors in similar ways and that the differences shown in nest site selection could negate some of these effects. We propose that habitats providing suitable nest microclimates will become increasingly important for the successful breeding of seabird species, particularly under predicted climate change scenarios.

Extreme urban–rural temperatures in the coastal city of Turku, Finland: Quantification and visualization based on a generalized additive model

Fundamental knowledge on the determinants of air temperatures across spatial and temporal scales is essential in climate change mitigation and adaptation. Spatial-based statistical modelling provides an efficient approach for the analysis and prediction of air temperatures in human-modified environments at high spatial accuracy. The aim of the study was firstly, to analyse the environmental factors affecting extreme air temperature conditions in a coastal high-latitude city and secondly, to explore the applicability of generalized additive model (GAM) in the study of urban–rural temperatures. We utilized air temperature data from 50 permanent temperature logger stations and extensive geospatial environmental data on different scales from Turku, SW Finland. We selected five temperature situations (cases) and altogether 12 urban and natural explanatory variables for the analyses. The results displayed that (i) water bodies and topographical conditions were often more important than urban variables in controlling the spatial variability of extreme air temperatures, (ii) case specificity of the explanatory variables and their scales should be considered in the analyses and (iii) GAM was highly suitable in quantifying and visualizing the relations between urban–rural temperatures and environmental determinants at local scales. The results promote the use of GAMs in spatial-based statistical modelling of air temperature in future.

A Multi-Methodological Approach to Determine Permafrost Occurrence and Ground Surface Subsidence in Mountain Terrain, Tyrol, Austria

This study evaluates the potential of using high-resolution remote sensing data to detect permafrost patterns in a recently deglaciated alpine area on the mountain ridge of ‘Rofenberg’, Tyrol, Austria. Here, small but continuous settling of the surface was detected in differential digital terrain models throughout an annual airborne laser scanning (ALS) data series (2001–11). The settling is hypothesised to result from thawing of perennially frozen ground. To test this hypothesis, we applied a combination of established methods –geomorphological observations, permafrost modelling, near-surface ground temperature measurements (bottom of the winter snowpack and temperature logging) and geophysical surveys (electrical resistivity tomography, ground penetrating radar, seismic refraction) – that revealed the occurrence of permafrost in recently deglaciated terrain (above 3100 m asl). Consequently, the surface changes detected in the ALS data series are attributed to permafrost thaw and serve as a possible indicator of permafrost occurrence. The applied geophysical measurements also elucidate the recent development of permafrost after glacier recession since the Little Ice Age. However, to prove the existence of permafrost and its possible degradation, ALS data alone are insufficient and a combination of methods is recommended. Copyright © 2016 John Wiley & Sons, Ltd.

Daytime Variation of Urban Heat Islands: The Case Study of Doha, Qatar

Recent evidence suggests that urban forms and materials can help to mediate temporal variation of microclimates and that landscape modifications can potentially reduce temperatures and increase accessibility to outdoor environments. To understand the relationship between urban form and temperature moderation, we examined the spatial and temporal variation of air temperature throughout one desert city—Doha, Qatar—by conducting vehicle traverses using highly resolved temperature and GPS data logs to determine spatial differences in summertime air temperatures. To help explain near-surface air temperatures using land cover variables, we employed three statistical approaches: Ordinary Least Squares (OLS), Regression Tree Analysis (RTA), and Random Forest (RF). We validated the predictions of the statistical models by computing the Root Mean Square Error (RMSE) and discovered that temporal variations in urban heat are mediated by different factors throughout the day. The average RMSE for OLS, RTA and RF is 1.25, 0.96, and 0.65 (in Celsius), respectively, suggesting that the RF is the best model for predicting near-surface air temperatures at this study site. We conclude by recommending the features of the landscape that have the greatest potential for reducing extreme heat in arid climates.

In-situ coal seam and overburden permeability characterization combining downhole flow meter and temperature logs.

Abstract The planning and design of any coal mine development requires among others a thorough investigation of the geological, geotechnical and hydrogeological subsurface conditions. As part of a coal mine exploration program we conducted heat pulse vertical flow meter testing. The flow data were combined with absolute and differential temperature logging data to gain information about the hydraulic characteristics of two different coal seams and their over- and interburden. For the strata that were localised based on geophysical logging data including density, gamma ray and resistivity hydraulic properties were quantified. We demonstrate that the temperature log response complements the flow meter log response. A coupling of both methods is therefore recommended to get an insight into the hydraulic conditions in a coal seam and its overburden.

Upslope Internal-Wave Stokes Drift, and Compensating Downslope Eulerian Mean Currents, Observed above a Lakebed

AbstractIn a small lake, where flows were dominated by internal waves with 10–32-h period, slow but persistent mean transport of water over many wave periods was examined. Acoustic Doppler profilers (ADPs) and a vertical string of temperature loggers were deployed where the lower thermocline intersected the sloping lakebed. Near (<1 m above) the bed, internal waves, coherent with a lakewide seiche, propagated upslope at ~0.023 m s−1. Near-bed wave-induced water velocity fluctuations had a standard deviation of <0.02 m s−1. Near the surface, velocity fluctuations had similar magnitude, but lateral wave propagation was unclear. Averaged over many wave periods, the near-bed Eulerian velocity flowed downslope at ~0.01 m s−1, and was roughly cancelled by an upslope internal-wave Stokes drift (estimated by assuming that weakly nonlinear waves propagated without change of form). To examine net transport, while relaxing approximations used to estimate the Stokes drift, the observed temperature range (9°–25°C) was divided into 0.5°C increments, and the depth-integrated, wave-averaged flux of water in each temperature class was calculated. The coldest (near-bed) water was slowly transported onshore, opposite the Eulerian mean velocity. Onshore flux of warm near-surface water was comparable to an Eulerian-mean flux, indicating minimal near-surface Stokes drift. Intermediate water, from the middle of the water column and the outer boundary layer, was transported offshore by an offshore Stokes drift. The downslope near-bed Eulerian mean velocity, together with intensification of mean stratification within 0.4 m of the bed, may enhance boundary layer mixing.

Over-Winter Channel Bed Temperature Regimes Generated by Contrasting Snow Accumulation in a High Arctic River

We report experimental results of near-surface winter temperatures along and adjacent to the channel bed of a High Arctic river on Melville Island, Canada. Temperature loggers 5 cm below the ground surface in areas where the terrain suggests varying snow accumulation patterns revealed that the maximum winter difference between air and near-surface temperatures ranged from 0 to +30°C during the winter of 2012–13, and that shallow near-surface freezing conditions were delayed for up to 21 days in some locations. Cooling to -10°C was delayed for up to 117 days. Modelled temperature at the top of permafrost indicates that permafrost at locations with thick snow can be up to 8°C warmer than those with thin snow. This thermal evidence for an ameliorated surface environment indicates the potential for substantial extended microbial and biogeochemical cycling during early winter. Rapid thaw of the bed during initiation of snowmelt in spring also indicates a high degree of hydrological connectivity. Therefore, snow-filled channels may contribute to biogeochemical and aquatic cycling in High Arctic rivers. Copyright © 2016 John Wiley & Sons, Ltd.

Internal tides recorded at ocean bottom off the coast of Southeast Taiwan

AbstractAn ocean‐bottom experiment consisting of an array of four ocean‐bottom seismometers (OBS) was conducted off the coast of southeast Taiwan during May–July 2011. We develop comprehensive analyses of the space‐time kinematics of the tidal signals recorded in the compact high‐sensitivity temperature loggers (CHTL) and the OBS geophones at the ocean bottom with depths ranging from 1254 to 1610 m. The evidence suggests that internal tides are responsible for the recorded signals: baroclinic internal waves (mainly the M2 tide) are generated by barotropic tidal currents in the Luzon Strait. The internal tides exhibit gradual phase changing and irregularly fluctuating strength, leaving signatures in the CHTL as ambient temperature variations, signifying low‐mode wave motions within the stratified water layers; and in OBS geophones as intermittent “tremor” agitations, signifying high‐mode turbulent flows on the seafloor. The M2 internal tides across our array are found to propagate in the northeast direction at speeds ranging from 1 to 2+ m s−1. Furthermore, the internal tides are identified at the ocean‐bottom based on an operational hydrodynamic hindcast/forecast model. The simulations show good agreement with the observed temperature variation on the seafloor and substantiate the vertical velocity and displacement of the water parcel driven by the internal tides. The joint detection of the temperature and tremor signals provides further information about the interactions of internal tides with the seafloor topography and the associated energy dissipation. Our results elucidate the space‐time ubiquity of the internal tides at the ocean bottom, which is an important interface of dynamic oceanography.

Improving the temperature predictions of subsurface thermal models by using high-quality input data. Part 2: A case study from the Danish-German border region

We present a 3D numerical crustal temperature model and analyse the present-day conductive thermal field of the Danish-German border region. The model region covers the northernmost part of the North German Basin, a transition zone between the deep-reaching sedimentary rocks of the Glückstadt Graben (including complex salt structures) and the shallow crystalline basement of the Ringkøbing-Fyn High. The modelling approach is novel as it implements for the first time a comprehensive analysis of well-log data on a regional modelling scale. Those logs were used both to derive the spatial distribution of rock thermal conductivity across the study area, and to calculate heat flow values. New values of terrestrial surface heat flow are reported for eight deep boreholes in the North German Basin ranging from 72 to 84mW/m2 with a mean of 80±5mW/m2. The values are computed from continuous temperature logs, carefully corrected BHT values, drill-stem tests and well-log derived rock thermal properties (thermal conductivity, radiogenic heat production) and were included in the setup of the numerical lower boundary conditions. New surface heat flow is up to 20mW/m2 higher than low values reported in some previous studies for this region. Heat flow from the mantle is 33–40mW/m2.The model temperature predictions are validated against 59 temperature observations from 24 wells. The prediction uncertainties between observed and modelled temperatures at deep borehole sites are small (rms=3.5°C, ame=2.1°C). Pronounced lateral temperature variations are predicted and found to be caused mainly by complex geological structures, including a large amount of salt structures and marked lateral variations in the thickness of basin sediments. The associated variations in rock thermal conductivity generate significant variations in model heat flow and large variations in temperature gradients.With regard to the utilization of geothermal energy, the Rhaetian and the Middle Buntsandstein sandstone reservoirs are found with temperatures within the range of 40–80°C, suitable for low enthalpy heating purposes, in most of the area and locally also with higher temperatures. Temperatures above 120°C, of interest for the production of electricity, are observed only in the very southeastern part of the study area.

Analyzing airflow in static ice caves by using the calcFLOW method

Abstract. In this paper we present a method to detect airflow through ice caves and to quantify the corresponding airflow speeds by the use of temperature loggers. The time series of temperature observations at different loggers are cross-correlated. The time shift of best correlation corresponds to the travel time of the air and is used to derive the airflow speed between the loggers. We apply the method to test data observed inside Schellenberger Eishöhle (ice cave). The successful determination of airflow speeds depends on the existence of distinct temperature variations during the time span of interest. Moreover the airflow speed is assumed to be constant during the period used for the correlation analysis. Both requirements limit the applicability of the correlation analysis to determine instantaneous airflow speeds. Nevertheless the method is very helpful to characterize the general patterns of air movement and their slow temporal variations. The correlation analysis assumes a linear dependency between the correlated data. The good correlation we found for our test data confirms this assumption. We therefore in a second step estimate temperature biases and scale factors for the observed temperature variations by a least-squares adjustment. The observed phenomena, a warming and an attenuation of temperature variations, depending on the distance the air traveled inside the cave, are explained by a mixing of the inflowing air with the air inside the cave. Furthermore we test the significance of the determined parameters by a standard F test and study the sensitivity of the procedure to common manipulations of the original observations like smoothing. In the end we will give an outlook on possible applications and further development of this method.

A completion staging case study in the Barnett Shale using advanced LWD quadrapole sonic and borehole imaging

Horizontal completions within a complex oil condensate window of the Barnett Shale have proven challenging because of problematic well placement within an optimum reservoir section and the vertical and mechanical proximity to mobile water in the Viola Limestone. Accurate formation properties along the horizontal well are required to identify both conditions in order to effectively avoid water production.At the request of the operator, a post-mortem study was conducted on a horizontal well in the Lower Barnett Shale to determine the cause of excessive water production. Completion optimization studies are typically conducted using wireline tools; however, for the purposes of this study, an advanced LWD logging suite consisting of electromagnetic azimuthal resistivity, neutron, azimuthal density, laterolog resistivity imager, and quadrapole sonic was run on the well. An integrated interpretation of all sensor data was used to first confirm the stratigraphic placement of the well and then evaluate effective porosity, anisotropic closure stress, geologic texture, and natural fracture distribution.Fracture stages and cluster stages were then selected to target similar rock and lowest closure stress along the well, while taking into consideration the existing natural fractures determined from the image log. Fracture-stage placement data, chemically traced production flow, and a flowing temperature log were all used to interpret well flow vs. the actual perforation cluster positions.This paper presents conclusions drawn regarding both the engineering evaluation criteria used to fracture the well, as well as the geologic-based texture and fracture interpretation that explains the ultimate well performance. Finally, a new automatic staging and cluster-placement software solution was employed to use insight gained from the case study well to better plan future horizontal completions within the field.

Development and Characterization of a Continuous Tympanic Temperature Logging (CTTL) Probe for Bovine Animals

<abstract> Developing a research tool that is low cost, easy to install, and can be implemented in group-housed animals is important to quantify parameters needed to promptly assess animal health and well-being. However, a practical and cost-effective solution for monitoring large numbers of animals in a production setting has not been developed. The objectives of this study were to (1) develop a self-contained and easily deployed continuous tympanic temperature logging (CTTL) probe capable of recording and storing tympanic temperature (T_T) data from group-housed beef cattle, (2) determine the minimum sampling interval needed to measure T_T in beef cattle, and (3) quantify the temperature differences among the ears (left and right) and vagina (T_V). A two-part device was developed consisting of a temperature logger housed in a molded foam probe. The CTTL probe can be effectively used to measure T_T in both the left and right ears of group-housed animals. The CTTL is cheaper, faster, and easier to install and remove when compared to past methods. Recovery rate was greatly affected by cattle behavior, weather, duration of collection, and installer, but a recovery rate of ≥75% should be considered successful and ≤50% unsatisfactory. When planning research trials, increasing the number of required animals would compensate for a few dislodged temperature loggers. Periodogram analysis determined that a minimum effective sampling interval of 2.5 min (lower than in past studies) was needed to capture the dynamic nature of T_T in field conditions. Mean temperatures were different (p < 0.0001): 39.3°C, 38.5°C, and 38.4°C for T_V and T_T in the right and left ears, respectively. The mean temperature difference between the ears (left - right = -0.10°C) was smaller than the mean difference between the vagina and each ear (vagina - left ear = 0.92°C; vagina - right ear = 0.83°C). The variability in the temperature profiles both within and between animals presents difficulty in characterizing, modeling, and subsequent prediction of thermal status using mean values. Future research should be directed toward characterizing T_T profiles of beef cattle using signal analysis for different phenotypes and growth stages.

Log based petrophysical analysis of mio-pliocene sandstone reservoir encountered in well Rashidpur 4 of Bengal Basin in Bangladesh

Rashidpur is located in the northeastern part of Bangladesh which is surrounded on three sides by India and on a small portion by Myanmar. Gamma-ray, spontaneous potential, density, neutron, resistivity, caliper, temperature and sonic logs are used to analyze petrophysical parameters of the well Rashidpur 4, Bangladesh. Quantitative measurements of different factors such as shale volume, porosity, permeability, water saturation, hydrocarbon saturation and bulk volume of water are carried out using well logs. Petrographic and XRD results based on several core samples are also compared with log-derived parameters. Twenty permeable zones are identified whereby four are hydrocarbon bearing in the studied Mio-Pliocene reservoir sandstones. Measured shale volume ranges from 11% to 38% and porosity is 19% to 28%. However, log-derived porosity is slightly higher than the thin section porosity. Water saturation of the interested zones varies from 14% to 38%, 13% to 39% and 16% to 41% measured from Schlumberger, Fertl and Simandoux formula respectively. Conversely, hydrocarbon saturation of the examined hydrocarbon zones ranges from 62% to 86%, 61% to 83% and 59% to 84% respectively. In the analyzed zones, the permeability values are calculated as 28-305 mD. Good to very good quality hydrocarbon reservoirs are appraised for the studied four zones based on the petrophysical parameters, petrographic observation and XRD analysis. Among these, Zone 4 is the best quality reservoir for hydrocarbon.Bangladesh J. Sci. Ind. Res. 51(1), 23-34, 2016

Benthic Photo Survey: Software for Geotagging, Depth-tagging, and Classifying Photos from Survey Data and Producing Shapefiles for Habitat Mapping in GIS

Photo survey techniques are common for resource management, ecological research, and ground truthing for remote sensing but current data processing methods are cumbersome and inefficient. The Benthic Photo Survey (BPS) software described here was created to simplify the data processing and management tasks associated with photo surveys of underwater habitats. BPS is free and open source software written in Python with a QT graphical user interface. BPS takes a GPS log and jpeg images acquired by a diver or drop camera and assigns the GPS position to each photo based on time-stamps (i.e. geotagging). Depth and temperature can be assigned in a similar fashion (i.e. depth-tagging) using log files from an inexpensive consumer grade depth / temperature logger that can be attached to the camera. BPS provides the user with a simple interface to assign quantitative habitat and substrate classifications to each photo. Location, depth, temperature, habitat, and substrate data are all stored with the jpeg metadata in Exchangeable image file format (Exif). BPS can then export all of these data in a spatially explicit point shapefile format for use in GIS. BPS greatly reduces the time and skill required to turn photos into usable data thereby making photo survey methods more efficient and cost effective. BPS can also be used, as is, for other photo sampling techniques in terrestrial and aquatic environments and the open source code base offers numerous opportunities for expansion and customization.

Monitoring of a vertical borehole ground-coupled heat pump system: A case study from a marly-limestone heat reservoir (Urbino, Central Italy)

This paper presents a case study of a vertical borehole ground-coupled heat pump (GCHP) system operating in Urbino (Central Italy), and includes an assessment of its seasonal performance and impact on the sedimentary heat reservoir from October 2010 to October 2014. The GCHP is installed in a commercial building and monitored by means of temperature and thermal energy data loggers. The temperature of the ground heat reservoir at various depths is also monitored down to a depth of 100m, by means of temperature profiles measured along a borehole heat exchanger and in a monitoring well drilled ad hoc at a distance of 2.2m.Almost three years of plant monitoring has confirmed the high efficiency of both the heating and cooling cycles of the ground-coupled heat pump system and has highlighted the high performance of the free-cooling mode during the summer. In addition, unbalanced exploitation of the sedimentary heat reservoir during winter and summer seasons has led to a general decreasing trend of ground temperature over the monitoring period.The temporary effects of an unusually heavy snowfall and groundwater circulation on ground temperature is also discussed.

Use of shallow groundwater temperature profiles to infer climate and land use change: interpretation and measurement challenges

AbstractTemperature is often used to infer the effect of land use and climate conditions on aquifers. Reliable data are needed to examine the temperature behaviour in the subsurface; thus, the use of robust acquisition techniques is unavoidable. Three temperature measurement techniques were applied to assess the sources of bias that could occur during temperature logging in a shallow Quaternary coastal aquifer in Ferrara (Northern Italy). Open borehole temperature logging, multilevel sampling straddle packers isolated temperature measurements within a flow cell above ground and multilevel sampling straddle packers isolated temperature measurements via an in‐well level logger (MLS‐IW) were compared for several coastal monitoring wells to gain insights on the limitations of each technique. Results show that the source of bias between the three applied techniques are different: (i) the open borehole temperature logging method tends to record heat convection through the open borehole and is not representative of the aquifer temperature distribution; (ii) the multilevel sampling straddle packers isolated temperature measurements within a flow cell above ground method is swayed by the air temperature and the heating of the submersible pump used to lift groundwater above ground; and (iii) the MLS‐IW provides the most reliable vertical thermal profiling both in summer and winter, because groundwater temperature is directly measured at the selected monitoring depth. The implementation of a 1D flow model demonstrates that if precise temperature profiles are needed to infer the influence that land use and climate changes have on groundwater, the MLS‐IW method is a reliable method that could be applied to existing monitoring wells. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Influence of solar irradiance on underwater temperature recorded by temperature loggers on coral reefs

AbstractThe use of miniaturized digital temperature logging devices on coral reefs is increasing dramatically due to the threat of global warming. Shallow coral reef environments are characterized by extremely high solar radiation and highly transparent seawater, raising the possibility of solar heating of devices deployed in these settings. In this study, we compared temperature measurements under a variety of shading treatments to investigate the potential error associated with high irradiance levels in shallow, clear waters. Results of this experiment showed that mid‐day water temperature readings by unshaded loggers were significantly higher by 2.2°C on average compared with shaded loggers. Loggers shielded with reflective tape showed less error but still reported significant heating, with water temperatures that were on average 0.15°C higher than shaded loggers. There were no significant differences among shade treatments during nighttime hours, indicating that irradiance is the source of the errors documented here. Care must be taken to shield temperature loggers from irradiance while providing good circulation of water around the sensors. One option is to place the loggers in a naturally occurring, cryptic or shaded habitat on the reef. When deployed in open reef areas, in mesocosms, or in experimental aquaria, loggers can be shielded in protective, opaque plastic tubes that are open at both ends.

Urban roost temperatures of large-spotted-genets: The effect of anthropogenic structures

Generally, large-spotted genets (Genetta tigrina) use tree hollows and canopies as daytime roosts during their inactive phase. However, there has been an increasing tendency for individuals to make use of anthropogenic structures, such as roofs, within urban landscapes in KwaZulu-Natal, South Africa. This study investigated the roosting thermal dynamics of large-spotted genets within the urban suburbs of Kloof. Roost temperatures were recorded with i-Button® temperature loggers at known large-spotted genet roosts in anthropogenic structures as well as in natural roost sites. Over the seasons, temperatures varied significantly between months and among different roosts. However, anthropogenic roost temperatures were higher than ambient temperatures throughout the study period. Furthermore, anthropogenic roosts had higher temperatures (with lower variability) than natural roost sites. This study highlighted the importance of anthropogenic structures as daytime roosts for large-spotted genets within an urban mosaic. However, high temperatures experienced during the summer can be detrimental to juvenile large-spotted genets resulting in plasticity of breeding behaviour and a switch to producing young in cooler months.

Comparison of Two Methods for Determination of the Insulation of Passerine Nest Walls

Several methods have been used to determine the thermal properties of nests and in the last few years small iButton® temperature loggers have been used to determine an insulatory value. A recent study on Common Bullfinch ( Pyrrhula pyrrhula) nests used a different method, namely infrared (IR) thermography, to study nest wall insulation because pushing temperature loggers into the nest wall materials would have destroyed their structural integrity and probably adversely affected the insulatory value. Here, we compared the insulatory values of Common Linnet ( Carduelis cannabina) nests determined using temperature loggers (to record cooling rates in °C 20 s−1) with the temperature differences (ΔT in °C) across the nest wall as measured with IR thermography when the inside of the nest was heated under a steady state. Insulatory values were more variable than ΔT but there was no correlation between these two proxy measures of insulation. Despite being within the same family, Common Linnets build nests with very different materials from Common Bullfinches but ΔT values measured using IR thermography suggested that the nest wall of Common Linnet nests offered better insulation than the walls of Bullfinch nests. Our results suggest that comparative studies need to use the same methodologies but more research is needed to better understand the limitations of different methods in determining nest wall insulation.