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Question
A pair of Mockingbirds created a nest in one of our rose bushes. The bush is located in the front of our home. It is a well established bush that is a little taller than me (I am 5ft4in) and the nest was very well hidden. The only reason we found it was I noticed the Japanese Beatles were starting to feed on the new rose buds and I happened to notice a broken tree twig sticking out.  I went to pull it and that is when I saw the nest. Over the next few days it went from 1 egg to 4 eggs.  No one in the family touched the nest nor any of the branches, Yesterday evening my husband saw the 4 eggs when he took the dogs out and as he is much taller than me he can easily look over some of the branches without touching them and see the nest but this evening they are all missing. I thought I read somewhere that birds do not move their eggs but we didn't see any broken eggs under the rose bush nor anywhere else in the area.  We do live in an area with woods around our home.  Is it possible a snake could have gotten the eggs?  I know we have brown snakes as well as copperheads but very rarely see them.  
Respectfully, Nikki

Answer
Dear Nikki

Thank you for your question. I also wish to thank the authors of the websites I used.

http://www.biokids.umich.edu/critters/Mimus_polyglottos/ and http://eol.org/pages/1050704/details say that blue jays, fish crows, American crows, snakes and squirrels eat northern mockingbird eggs and chicks. Stephanie Pappas (http://www.livescience.com/14043-cats-hunt-mockingbird-chicks.html) says that cats will also eat the eggs and this could explain why you couldn't find any eggshells, as cats often carry their meals some distance before eating them.
The female often eats the eggshells, to replace the calcium used to make them in the first place. Otherwise, the parents will fly off to dispose of them a long way from the nest; the white inside of a shell is conspicuous, and if left near the nest might attract predators.


Resin (http://davesgarden.com/community/forums/t/1225438/#b) says that a female mockingbird often eats the eggshells to replace the calcium used to make them. Alternatively, the parents take the eggshells and fly a long way from the nest to dispose of them, as the white inside of an eggshell may attract predators. This means that the eggs may have hatched and that a predator may have eaten the chicks rather than the eggs, although the predators listed above (blue jays, fish crows, American crows, snakes, squirrels and cats) may have eaten the chicks. As you didn't find any eggshells, I think there is a strong possibility that a predator took the newly hatched chicks, perhaps when the parents were removing the eggshells and the chicks were more vulnerable.

I'm sorry I can't give you a definite answer to this question, as there are several possibilities.

All the best

Jonathan  

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Jonathan Wright

Expertise

I can answer questions about wild mammals and other animals, as well as extinct animals and zoos. I am not an expert about every animal species. I can look up information from books and the internet, but can't verify if all the information is true. Please don't ask questions about: 1. Pets. I am not a vet. Please contact a vet if your pet is ill. You may need to spend some money if you want your pet to live. Don't get a pet if you don't know how to look after it and if you can't provide it with the space, food and possible companions that will help it live a healthy life. Don't take animals from the wild, unless they are ill and/or injured and you can protect them until a wildlife charity can help. It is cruel to take animals from their parents, especially if the parents will look for the babies, while putting their other babies at risk. You may be breaking the law by keeping wild animals or you may need a licence to look after some species. Please check with a local wildlife group. 2. Eggs: Please don't remove eggs from nests. The mother birds provide the right temperature for the eggs and won't sit on them if the temperature is warm enough for them to develop naturally. It is illegal to remove eggs of some species and, unless you have an incubator or a broody hen, the egg may not develop. If you are allowed to touch the eggs, you can candle them to see if they are fertile. If theys aren't fertile, they won't hatch. 3. Fights: Please don't ask about fights between different animals. These questions assume that individuals of two species fight each time they meet and that one species will always be victorious over another. This is untrue. There are cases where a live mouse has been fed to a venomous snake, bitten the snake leading to the snake's demise. 4: Diseases: Please ask doctors or other medical experts about diseases that you may catch from animals. I can't advise on how to deal with viruses, bacteria etc.

Experience

I have a zoology degree and have been interested in animals since I was two. I am a zoo volunteer at London Zoo. I have appeared on a BBC Radio Quiz, 'Wildbrain'.

Organizations
WWF. ZSL. Natural History Museum. RSPB. London Bat Group.

Publications
Newsletters of London Zoo volunteers and the London Bat Group

Education/Credentials
BSC degree in Zoology. 'A' level in Zoology. 'O' Level in Biology.

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