A Management Protocol for Hand-Rearing Swifts

The protocol set out on this site is the result of the research conducted from 2008-2010, when data was collected not only from the experience at Torreferrussa, but also from other centres in Europe and the United States, and from private wildlife carers in various countries who spend their summers (and their money) in hand-rearing orphan chicks in such an excellent way.

The research outcome may seem obvious. The comment has been made that "it is normal for young insectivorous birds to do better if they are fed with insects." It may be a truism but this research confirms clearly that it is so.

More importantly, the research has demonstrated the opposite outcome i.e., how badly insectivorous chicks perform when they are NOT fed with insects.

This section details the hand-rearing protocol which has been adopted by the Torreferrussa Wildlife Rehabilitation Centre, which includes a major emphasis on a diet of mealworms (Tenebrio molitor). This diet has been adopted directly as a result of this research.

The results of this diet, solely insect based, when compared to the results from diets used in previous seasons (rat mince and cat food), demonstrate a remarkable optimisation in the hand-rearing and rehabilitation of Common Swifts in this Centre.


The diet has also proved highly successful with adult Common Swifts and Alpine Swifts.


The mealworm diet results

 


5g average weight increase in chicks which arrived as fledglings

A remarkable 7g weight increase in very young chicks

volander

poll

A notable increase in a species where adult weight is around 42 g


          A key factor in the survival in the wild

 

An increase of nearly 30 % in survival rates versus previous seasons

High recovery rates in extreme clinical conditions such as severe emaciation

 

The use of the mealworm diet proved that there was

in most of the cases no need to reject chicks

because of poor body condition or low weight

upon admission

 

Feather condition and flight

 

performance at release

 

was extremely more optimal 

 

when compared to the observed with previous diets

-The natural begging behaviour observed in nature

by all nestlings when parents arrive at the nest,

was acquired in a short time by nearly all hand-reared

chicks, even amongst those with more severe clinical

conditions.

-This behaviour was observed almost to the point of

release which helped the feeding process

enormously.

-When using non-insect based diets, the natural begging

behaviour was less obvious and it was necessary to

force-feed the chicks in the majority of cases

 

Non-insect based diets should be considered inappropriate and even harmful, 

such as the ones used in previous seasons composed of rat mince, or the diet used in the 2009 season which followed a formula based on a high-protein grain-free cat food, described in the literature as successful with insectivorous species.  


 

My objectives in seeking to promote the results of this research are:

  • Many wildlife rehabilitation centres are currently using non-insect based diets (mainly cat food) to hand-rear insectivorous bird species. The Internet is full of resources, theoretically reputable, which advise the use of diets such as cat food, to hand-rear insectivorous chicks. This incorrect advice runs the risk of being followed by professionals or even private individuals who decide to hand-rear chicks at home.
     
  • It is essential to be aware of the poor results from using these non-insect based diets. This is clearly demonstrated by the empirical data resulting from this research, which was based on a large sample of Common Swift chicks of different ages and different clinical conditions. This evidence could probably be extrapolated to all other insectivorous species, such as Swallows or House Martins.
     
  • We have to bear in mind that these inappropriate diets may jeopardise not only the survival during the hand-rearing process, but also survival once the bird is introduced back into the wild. It does not make sense for those involved professionally in wildlife rehabilitation to continue to use them when the outcome is now known.
     
  • The insects produced commercially are very expensive, thus many rehabilitation centres may not be able to afford these costs when hand-rearing large numbers of insectivorous orphans.A viable option is to use mealworms, a relatively cheaper insect (~ 20 € per kilo) when compared for example with the domestic cricket (Acheta domestica) (~ 80 € per kilo).
     
  • The aim of my research was to come up with a definitive diet that could be taken on by the range of rehabilitation centres but I do not in any way seek to present this diet as better than other insect-based diets. For instance, Mauersegler Klinik in Frankfurt, the main reference point for Common Swift rehabilitation, where Dr.Christiane Haupt leads the recovery treatment of this species, uses a diet based on crickets. Certainly I would consider the best diets to be ones composed of a greater variety of insect species, such as those used by private expert rehabilitators like Hilde Mathes in Germany or Gillian Westray in the UK (www.swift-conservation.org). Unfortunately, these diets are probably not a viable option when you are hand-rearing a very large number of chicks.
     
  • I need to acknowledge the fact that there is some controversy about the use of mealworms to hand-rear Common Swifts. The diet is based on and inspired by information set out in Kyle and Kyle (2004), which in turn is based on the long experience of experts in the United States  in hand rearing Chimney Swifts (Chaetura pelagica). Their experience demonstrates significant success rates in rehabilitation and also in recovery data in the years following release. This diet has also proved successful at Torreferrussa as a base diet for more than 800 chicks in the last season. In addition, histopathological analysis carried out on some individuals confirmed the absence of internal organ damage caused by the mealworm-based diet. Even with these results, I am far from wanting to create a mealworm vs cricket discussion, but most emphatically want to generate an insect vs non-insect one.
     
  • In relation to the mealworm diet, we have attempted to add in other insect species such as crickets (commercially produced), and species bred in the Centre such as silk worm (Bombyx mori), wax worm (Galleria melonella) and Argentinian cockroach (Blaptica dubia).These species may provide a useful supplement to the diet where mealworms represent the 90%. This was done basically for economical reasons and also because of difficulties with utilising certain other species. The cricket diet, which has also been proven to be successful, may simply be unsustainable in economic terms for hand-rearing the almost 800 Common Swifts (and other species such as Alpine Swifts) which arrive each season at the rehabilitation centre. The research results indicate that such investment may in any case be unnecessary.