RUM MANX SHEARWATER (Puffinus Puffinus) REPORT 2007   Introduction Rum is an NNR about 20 kilometres west of Mallaig and is the biggest of the Small Isles.  It is designated an SPA for its unique population of Manx Shearwaters holding between a quarter and a third of the world's population.  They breed above 400 metres (up to more than 700 metres).   Unlike other colonies which are virtually at sea level.   Annual monitoring of around 100 burrows has taken place since 1994 on Hallival.  In 1998 the author first saw rats in the colony in the breeding season.  It had been thought that rats came up to the colony to scavenge failed eggs and dead young at the end of the season in September.  The evidence for rats in the colony and having a detrimental effect on the Shearwaters grew and SNH decided that studies had to be undertaken to assess the problem.  Since 2006 monitoring of the breeding of Manx Shearwaters on Rum has been contracted out.   The work to be undertaken involved opening up study burrows on the three main sub-colonies - Hallival, Askival and Trollval) - the number of burrows in approximate proportion to the area of greens.  Burrows were dug up and each hole plugged with largish stones.  In addition a small cairn of stones was put beside each burrow and orange twine around either a nearby stone or a plug.  Each burrow  was GPSed.  Unfortunately relocating some of the burrows was difficult because the GPS does not work well where there are steep slopes or cliffs (sometimes overhanging) and deer or goats tended to kick some small cairns away and were quite interested in the twine!  Weather has created havoc on a number of occasions.  Burrows were opened up on Trollval but it is a difficult area to dig due to structure of stones in the greens.  In addition there is the problem of access - it is necessary to go up from Harris. Dates of visits Visits were made as follows 30-31st March 8-9 May  for visual assessment. 21-25 May Largely rained off!! 15-21st June for opening up study burrows and a tape playback study. 14-16 July 25-29th July wet! 11-14th Aug  very wet! 26-29th August – again very wet! 3-4 Sept 6th Sept 10th Sept 12-14th Sept 17th Sept 25-30th Sept Visual Assessment In an attempt to callibrate tape playback for occupancy a visual assessment was made of the previous years' study burrows.  This involved identifying whether the burrow had been excavated; whether droppings were evident and how much trampling at the burrow entrance.  If birds are undertaking housekeeping then this should be considered an apparently occupied burrow.  There are three possible assessments - occupied, not occupied and probably occupied.  Results below. Results of Visual assessment of burrow2007                   Occup     not occ Prob occ   Number 82 16             8   Act occ 80 2             5   % acc 98 88 63   Overall acc   93               93% is a good figure and similar to that achieved on Canna in the 1970s.  Please note that occupied means at least a nest.  Tape Playback  During a week in mid - June tape playback experiments were conducted and results would be available later - work undertaken for Wales Nature.  It was interesting that there was not a very high degree of consistency with some individual birds responding one day and not the next  and vice versa.  In addition birds responded while "squatting" in an empty burrow.  While it is good to have consistent methods of censusing a colony it would be useful to have the Rum censusing done by the visual method early in the season.  Timing of Breeding Season 2007 breeding season was the more protracted than most but not as much as 2006.  The median laying date was estimated at 25th May - extremes 28th April and 21st June. This assumes average hatching as 51 days and fledging 71 days (Brooke).  2006 was a fairly synchronised breeding season on Askival but not on Hallival.  However 2007 was not nearly so synchronised as Askival.  This was the first year that there were lots of rat signs on Askival in the colony. One possible reason for the protracted season is pressure from rats -  the rats cannot live in small rat holes due to their size and presumably live in Shearwater burrows - we saw plenty evidence that they do in mid-winter during winter 2006/2007.  Perhaps  birds are stressed by rat interference and this affects the whole breeding process including delay in breeding.  Assessing this would be very difficult.   Productivity YEAR       AREA                                            1 2 3 4 5 All areas     1995 Productivity 0.83 0.77 0.85 0.93 no data 0.85       occupancy 67 79 75 93 no data 78     1996 Productivity 0.67 0.75 0.77 0.67 no data 0.72       occupancy 72 93 86 94 no data 86     1997 Productivity 0.82 0.87 0.89 0.94 0.88 0.88       occupancy 44 85 75 49 63 63     1998 Productivity 0.64 0.06 0.45 0.13 1 0.30       occupancy 67 46 81 73 26 66     1999 Productivity 0.39 0.44 0.76 0.67 0.50 0.55       Occupancy 75 67 68 56 46 62     2000 Productivity 0.65 0.71 0.62 0.67 0.67 0.66       Occupancy 68 78 70 72 68 71     2001 Productivity 0.67 0.85 0.67 0.67 0.63 0.73       Occupancy 60 87 70 60 83 74     2002 Productivity 0.62 0.67 0.75 0.71 0.81 0.73       Occupancy 68 92 80 78 82 80     2003 Productivity 0.68 0.68 0.74 0.92 0.79 0.75       Occupancy 76 86 79 86 88 82     2004 Productivity 0.67 0.61 0.6 0.63 0.6 0.62       Occupancy 79 78 72 70 77 76     2005 Productivity 0.59 0.63 0.5 0.53 0.63 0.57       Occupancy 81 64 71 71 53 69   More information to be submitted.