SquirrelWeb

On 1st January 2005, Maria Salmon wrote to say that she has a problem with a grey squirrel who is stealing pebbles, about the size of a walnut, from her garden, and she wondered if anyone had heard of or seen this unusual behaviour, and why the squirrel was doing it? Maria would also like to know if there is a way to stop the squirrel stealing the pebbles. She says that it was quite amusing when it first started a few months ago but it had reached the point where they will have to buy more pebbles to replace all those taken away. She believes the squirrel takes pebbles on most days but she has never found out where it takes them. Her property backs onto a park and the squirrel does not always go in the same direction when it leaves the garden. Maria feeds the squirrels in her garden, but this particular one normal ignores the food and just keeps taking the pebbles.

Maria continues the story on 24th February. She thought that the squirrel might have stopped its unusual behaviour, but it reappeared and started removing pebbles from another area in the garden since the original place has few pebbles left. Maria says they have quite a few squirrels that come into the garden but she assumes it is the same animal that has a penchant for pebbles. The other squirrels are only interested in the nuts put out, but this one just, goes straight for the pebbles, picks one up and goes straight off to do whatever it does with it.

The SquirrelWeb team is just as intrigued by this story as Maria, but we can offer no explanation. So, if anyone has seen this or similar unusual behaviour, please contact us or Maria directly (maria [dot symbol] salmon38 [at symbol] tiscali [dot symbol] co [dot symbol] uk).

The SquirrelWeb team will soon post all sightings of squirrels sent in on a new webpage in SquirrelWeb. Thus, all sightings of red squirrels, unusual colour morphs, or other squirrel observations, will be welcome.

Nicolas Ramos and John Koprowski

The conservation and ecology of Mearns’s Squirrel (Tamiasciurus mearnsi) in Sierra San Pedro Martir, Baja California, Mexico

The Mearns’s squirrel is an montane island endemic found in the highest regions of Baja California’s greatest mountain range at elevations around 3000 m. The species is considered to be threatened in Mexico and no ecological studies have been conducted. In addition, eastern gray squirrels (Sciurus carolinensis) were introduced to lower elevations over 50 years ago and their status is unknown. Related species in the United States typically larderhoard conifer cones. In our first visit to the region in November 2004, we caught glimpses of only two animals and did not find any larderhoards suggesting the behavior and ecology of this species may be quite interesting. Field efforts will begin in spring 2005 with plans to capture and radiocollar animals to assess their habitat use and basic ecology. The project will continue for at least 4 years and we will continue to update this site as we obtain additional information. Please do not hesitate to contact us if you have further questions.

Nicolas Ramos, Ph.D. student, Wildlife Conservation and Management, School of Natural Resources, University of Arizona, Tucson, AZ, 85721, USA, 

John L. Koprowski, Associate Professor, Wildlife Conservation and Management, School of Natural Resources, University of Arizona, Tucson, AZ, 85721, USA. 

JNCC and PTES are funding a new red squirrel monitoring study to start in January 2005 and will continue for 2 years. The aim is to produce recommendations and costings for an effective red squirrel surveillance scheme in the UK. The study will be carried out by Robbie McDonald (Quercus, School of Biology and Biochemistry, Queen’s University Belfast, Sarah Cartmel (Gwynedd, Wales), Peter Lurz (Centre for Life Sciences Modelling, University of Newcastle-upon-Tyne) and John Gurnell (University of London), and will involve volunteers. More information will be posted next year.

The SquirrelWeb Team would like to wish all our readers a happy festive season and a prosperous New Year.

John Koprowski

Arizona gray squirrels (Sciurus arizonensis) were first described about 150 years ago, yet there has not been a single publication on the ecology of this species. Often considered to be uncommon in the mountain islands of the deserts of Arizona and extending slightly into northern Mexico where the species is considered to be threatened, little is known of this large bodied tree squirrels (600-800 g). Introductions of Abert’s squirrels (Sciurus aberti) in the 1940s to many of the isolated mountains in which Arizona gray squirrels are found has been suggested to be a threat to the persistence of the uncommon natives. I have initiated studies in the Santa Catalina and Rincon Mountains of southeastern Arizona to assess current distribution of these species. Initial surveys suggest that Abert’s squirrels are common in the high elevation conifer forests where most museum specimens of Arizona gray squirrels were once collected. Arizona gray squirrels now appear uncommon in such habitats. During 2005, I will initiate a live trapping and radiotelemetric study to assess space and habitat use of these congeners in areas of syntopy and allotopy. The project is funded through 2006.

John L. Koprowski, Associate Professor, Wildlife Conservation and Management, School of Natural Resources, University of Arizona, Tucson, AZ, 85721, USA. 

Simon Bell from the Natural History Unit, BBC, Bristol has confirmed that a new programme about squirrels in the Wildlife on One Series will be broadcast on Thursday 11th November – it is called SQUIRRELS – Are They Tough Enough?

Marleen Vermeulen, a biology student from Antwerp, Belgium, is working on this project under the supervision of Luc Wauters as part of the collaboration in alpine squirrel research between the University of Insubria, Varese, Italy and the Research Group of Animal Ecology, University of Antwerp, Belgium.

Amanda Lloyd

Thesis abstract: Red and grey squirrel populations (Sciurus vulgaris and S. carolinensis respectively) and the influence of forest management were studied in Kielder forest, Northumberland and Creech forest, Hampshire between 1998 and 2001. The majority of the work was carried out in Kielder, an upland conifer plantation consisting primarily of Sitka spruce (Picea sitchensis), a non-native conifer species. The site at Creech was an ancient/semi-natural wood with large areas of Corsican pine (Pinus nigra).

Hairtube and live capture trapping were used to investigate the presence-absence of red squirrels in Kielder forest. Regression of hairtubes use against trapping in habitat- specific types allowed the prediction of the number of red squirrels using hairtubes in mixed conifer crops in upland habitats. The utility by red squirrels of mixed-species crops was higher than pure crops with the level of use changing on a yearly but not a seasonal basis. Hairtubes were used to collect presence-absence data from two forest blocks in Northumberland and the Borders in order to investigate the influence of habitat features of the spatial and temporal distribution of red squirrels. The data was modelled using logistic regression and linear relationships were found to exist between the utility of the hairtubes and the distance to clear fells for both of the forest sites along with the year of the survey. The effect of the clear fell distance on the utility of hairtubes is discussed with relation to food, habitat and fragmentation effects on squirrels.

Tree seed predictability, squirrel cone selection and seed morphometrics were investigated using a number of approaches including large-scale Forest research cone surveys, coneline data, and bomb calorimetry. Overall squirrels showed the least preference for Sitka spruce cones. There was differential selection for cones within the forest stands with peaks for production and consumption at 4 m and 10 m into the stands. Norway spruce seeds had the heaviest seed weight and calorific value, whilst Sitka spruce seeds had the lowest for both variables.

The impact of coning on a red squirrel population was investigated using an existing Spatially Explicit Population Model incorporating the observed seed energy data. The modelled squirrel population did not fluctuate in response to changes in seed energy. The scenario that made every year a good mast year, had an effect by doubling the population and density from 1 squirrel per 5.69ha to 1 squirrel per 3.42ha. The possible reasons behind this and future recommendations are discussed.

The effects of clear felling on a population of grey squirrels was investigated in Creech (Hants). Of the original 6 individuals, 3 either died or left the study area during the period of fieldwork, therefore only a sufficient amount of data for 3 squirrels was collected. Of these 3 squirrels, the home ranges were 25% smaller than grey squirrels in similar habitat consisting of semi-natural/Corsican pine woodland, suggesting a higher density population (~1 squirrel per ha) than Smith’s (1999) findings. On average these home ranges decreased in size after the clear felling had ceased, however 2 of the squirrels increased their core areas. At least 1 of the squirrels was pregnant during the month prior to felling, which may explain some of the ranging behaviour observed. It was however more likely that the squirrels were shifting their ranges in response to food availability rather than as a response to the impacts of clear felling.

Amanda Lloyd email: 

In the past SquirrelWeb has received sightings of squirrels that are unusually coloured. For example, recently we have received a report of a light creamy beige coloured ‘grey’ squirrel with a white underside, and only a hint of grey on its tail, from London, Ontario, Canada from Elisa Knight, and on 30th June this year Tom O’Brien says he saw a dark reddy-brown squirrel with white underside at Chillesford Forest (Explorer map 212 map ref 531377) in East Anglia, UK. It is possible that this was a red squirrel, which is of interest since they are believed to have disappeared from that part of England. If we get enough interest, SquirrelWeb will consider posting such sightings on a webpage.