Re: mixing bone meal and blood meal

James,

This is a good question that required a few schools of thought to answer.  
I elicited some help from an avian toxicologist, avian veterinarians, and 
avian nutritionists.  The majority of the answer was provided by Tom W. 
Smith, Professor of Poultry Science, Mississippi State University. 
Who graciously offered his expertise.

Everyone seemed to concur that there is no nutritional reason not to use 
either blood meal or bone meal.  However, you need to determine why you 
would need to add either of these or any unnatural ingredients.  Suet is 
normally used for supplementing the dietary energy level of wild
birds.  This is usually done during cold weather or when birds are 
preparing for migration.  Protein in either of these situations is not the 
essential factor, energy is.

Blood meal is an extremely high source of protein commonly utilized as an 
ingredient in commercial livestock feeds.  But increasing the protein level 
of the suet does not increase the energy level by very much.  This is 
because the best and most concentrated dietary energy source is fat, and 
lets face it, suet is fat!  Therefore, if you replace the fat with blood 
meal, you reduce the most desirable attribute of the suet, that being 
energy, in order to up the protein level which is not as essential. 

If you were to use bone meal, you would add extra filler without adding 
energy or protein. Bone meal has high levels of minerals such as calcium 
and phosphorus, but few other nutrients.  These minerals may be more 
important to birds at other times of the year, such as during mating and 
egg production, but are not be as essential to the wintering birds
who are primarily looking for a concentrated high source of energy. Again 
while bone meal can be included in the suet without harm, like blood meal, 
you should justify why it is being used.  Unless there is a specific reason 
for adding an ingredient it should not be used.

So James, while there are no risks from using either of these ingredients, 
few benefits would be gained. Suet is offered as a winter food substitute 
for insect eating birds such as woodpeckers and chickadees.  The lard or 
rendered fat, the main ingredient of suet, satisfies the basic energy needs 
of these birds. However, there are variations on this theme and you can 
find hundreds of "Suet Recipes" available on the net. Some links to suet 
recipes are listed below.  Some people add raisins, seeds, fruits, corn 
meal, etc. to make the suet more attractive to various birds.  Foods with 
high fat levels such as nuts, and peanut butter also lend themselves easily 
to a suet recipe and are closer to these birds natural diets, which rarely 
include bone or blood in any form.  

I hope this helps.


Steven Williams
           

Suet Links:
 Http://www.birdsforever.com
/suetrec.html http://web.mountain.net/
~shalaway/suet.html http://www.chirp.org/articles
/suet.htm