Statistics for 2005

2005 saw an early start to the breeding season, and a final count of 112 fledged young, from 150 eggs laid. The swifts began to return from Africa during April and May.

• 15th May 2005
  31 Boxes occupied; 16 eggs counted; a clutch of 3 eggs in one box. This is an exceptionally early start to the breeding season.
  
  
• 21st May 2005
  53 Boxes occupied; only 6 eggs visible.
  At this stage in the breeding cycle the birds are easily disturbed and may desert the nest if frightened, we do not need to have an accurate count of eggs yet as this data will become apparent in a week or two.
  
  
• 28th May 2005
  49 Boxes occupied; 18 eggs visible.
  Some pairs may have abandoned the breeding attempt due to the recent cold weather; time will tell if they recommence nest building so we will continue to monitor all nests.
  
  
• 4th June 2005
  66 Boxes occupied; 36 eggs visible; the first youngster has hatched!
  Some pairs may have abandoned the nesting attempt due to the recent cold and wet weather; we continue to monitor all nests and today found the first hatched chick. Nesting box W4B has 4 eggs, very unusual for swifts as they normally have 2 or 3 eggs.
  
  
• 11th June 2005
  66 Boxes occupied; 57 eggs visible; 40 youngsters.
  The Swifts have been busy during the past week, warm and dry conditions have provided ideal conditions for hatching youngsters. Some nests are still not accurately counted due to adults sitting and covering the contents - all will become clear in time.
  
  
• 18th June 2005
  66 Boxes occupied; 44 eggs visible; 82 youngsters.
  Warm and dry conditions have provided ideal conditions for hatching youngsters so the Swifts have been busy during the past week. Some nests are still not accurately counted due to adults sitting and covering the contents. We expect about 100 young swifts this year!
  
  
• 25th June 2005
  66 Boxes occupied; 3 eggs visible; 44 youngsters visible.
  Wet conditions during the week and a cool weekend mean that the adults are sitting in the boxes so an accurate count is not possible. We now expect more than 100 young swifts this year!
  
  
• 3rd July 2005
  66 Boxes occupied; 16 eggs visible; 103 youngsters.
  Warm weather has provided ideal conditions for youngsters so the Swifts have been busy during the past week. 17 young have been ringed and two adult pairs are now identified to the nesting boxes that they are using. We will fledge over 100 young swifts this year! The first youngster should leave the nest around the 18th July.
  
  
• 10th July 2005
  66 Boxes occupied; 3 eggs visible; 112 youngsters.
  They're off! The first youngsters left nesting box W19 around 8th July.
  When young birds leave the Oxford University Museum Colony we are extremely unlikely to see them again. Adults however, use the same nesting box year after year unless the pair breaks up. Even then the surviving adult is usually to be found in a nearby box.
  Swifts have been busy feeding during the past week; the continued warm weather has provided ideal conditions for the fast growing youngsters. About 50 young have been ringed and three adult pairs are now identified to the nesting boxes that they are using. We expect to fledge over 110 young swifts this year!
  
  
• 16th July 2005
  66 Boxes occupied; 3 eggs visible; 100 youngsters; 8 young fledged.
  Hot weather has enabled the youngsters to grow rapidly. 78 young have been ringed, eight have already fledged but 100 remain in the nest boxes. Several adult pairs are now identified to the nesting boxes that they are using; every year we attempt to catch and identify at least 50 adults as part of a BTO population study into the survival rates of swifts, although we can recognise the age of the birds we cannot tell what sex they are.
  
  
• 23rd July 2005
  66 Boxes occupied; 1 egg visible; 46 youngsters; 74 young fledged.
  The main population of young are starting to leave for Africa already; they are unlikely to return to this colony again. Adults return to the same box year after year.
  
  
• 30th July 2005
  24 Boxes occupied; 40 youngsters remaining; 6 young to be ringed.
  Wet and mild weather slowed down the rapid growth of youngsters. Many more adults are now identified. One chick hatched during the past week and should be ready to leave the colony in mid-September. Most of our remaining young will depart during the next two weeks.
  
  
• 6th August 2005
  9 Boxes occupied; 15 youngsters remaining; 1 young to be ringed.
  The excitement is almost over for another year. Swifts are rapidly disappearing to the south; very little screaming is heard around the tower. We are always sad to see these birds go but pleased to welcome them back the next May.
  
  
• 13th August 2005
  7 Boxes occupied; 11 youngsters remaining; all young ringed.
  The tower is quiet now, only an occasional burst of sound as an adult arrives with food. We have ringed 111 young this year so the swifts have enjoyed another successful breeding season. 22 adults were also ringed and 35 breeding adults with rings were identified. Many of the remaining young are large and ready to fledge soon.
  
  
• 20th August 2005
  1 Boxes occupied; 1 youngster remaining.
  Swifts are rapidly disappearing on migration; the last youngster is well grown and will soon depart. There will be no more screaming parties around our towns and villages until next year when the birds will again build nests and start to breed.
  
  
• 27th August 2005
  Last youngster fledged at 11.05am. 112 fledged from 150 eggs laid.

The average numbers of young swifts ringed each year over the last 40 years are:

• 1963-1972 36.7
• 1973-1982 70.4
• 1983-1992 100.0
• 1993-2002 99.2

Swifts at the Museum

© Oxford University Museum of Natural History