Life-Cycle Sleuth
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The Ruby Throated Hummingbird
by Jennine L.
Class 703- Dolphin Senior Public School
Mississauga, Ontario

Introduction
The Ruby-throated Hummingbird (also known as the Archilochus Colubris) is mainly nectar slurping bird. The male Ruby-throated Hummingbird has a ruby coloured throat and an iridescent lime green breast. It has a mainly white belly.The female on the other hand is not as brightly coloured as the male, so that attention is not drawn to then during the mating season. The female's underparts are mainly green, with whitish and unmarked underparts. Both the male and female's beaks are long, slim and black, which is ideal for slurping flower nectar.
The average weight for a male Ruby-throat is about the same as two and a half paper clips, which is about three grammes. They are also only about 4 centimetres in length, which means they 'i can glide through the air at incredible speeds. They are so small that they are often mistaken for moths. Every fall the Ruby-throat make the 960-kilometre trip down to Mexico where it spends the winter. The hardest part of their migration is making the journey across the Gulf of Mexico.


In the European ages the Ruby-throated Hummingbird was often caught and stuffed for decoration. This was a sign of great wealth. The Ruby-throated Hummingbird inhabits most of North Eastern North America during the summer months and then takes a 960-kilometre journey down to Mexico where it spends the winter. The male Ruby-throats migrates to Mexico a little bit earlier than the females do. The average temperature in Ontario (which is where they spend some of Spring, all Summer and a little bit of fall) is about 19 degrees Celsius and Mexico's average winter temperature is about 11 degrees Celsius. That is where they spend the rest of the year, except for the time they spend migrating. Both migrating there and back are very difficult trips, because they have to cross the Gulf of Mexico. Probably the hardest part of their journey is having to store enough fat to be able to make the crossings. Each year only about 50% of the Ruby-throats survive, but it is a very important trip that they make, because they have to have food in the winter and they need to mate in hot temperatures in the Spring, so they need to return to North Eastern North America.

The Ruby-Throat spends most of it's time around gardens, wood edges, streams and parks, because this is where they can find flowers most easily. In the Spring the male's territory is usually about 1/10 of a hectare.

The Ruby-throated Hummingbird is an almost entirely nectar eating bird, but also eats bugs, insects, small spiders and sap from the sapsucker when holes have been drilled in it. They prefer flower nectar, but when it isn't available they eat whatever is close and they are able to catch.

The Ruby-throat eats one half of its body weight each day, because of its incredible wing speeds it burns food off very quickly. They only weigh about the same as two and a half paper clips (which is about one and a half grams) Mainly bugs, insects and small spiders eat plants and sometimes smaller insects and they in turn eat mostly trees, shrubs, bushes and other kinds of plants.

The Ruby-throated Hummingbird does not have very many predators, so in a way it is at the top of its small food chain. They mainly eat nectar and when it is necessary they will use bugs and insects as a back up food supply. In turn nectar comes from flowers. Bugs and insect depend on plants and vegetation and also smaller insects. Which in turn all depend on plants, water and sun light. (Please turn the page to see the table.)

Cold and freezing temperatures mean that the Ruby-throats food supply becomes scares. The flowers and insects that they depend on either die or find another place that they could use for their shelter. When the photoperiod becomes longer the Ruby-throat knows that it is time for it to fly back to its summering ground. The photoperiod also tells the flowers to start shooting out of the ground and the insects that it is time for the new babies to hatch. The Ruby-throated Hummingbird spends many hours of the day looking for food. They slurp nectar with their long slender beak from the flowers that they find. It can also catch insects on the wing or on the ground and swallows them whole. Cold temperatures really affect how the Ruby-throat eats, because all of the plants and insects that they depend on for food aren't there for them anymore. They can't live more than a couple of hour in the cold weather without food, so it is very important for then to have a dependable food source.

Physiology
Cold temperatures affect Ruby-throat in many ways, because it means that they have to migrate approximately 960- kilometres across the Gulf of Mexico. It has to migrate, because all of the flowers die off in Eastern Canada and many of the insects can't live either, so they have to relocate themselves so that they can have enough food. The Ruby-throated Hummingbird prefers flower nectar to insects, so even though some insects can live through the winter they migrate down to Mexico so they can still have nectar for the main part of their diet. The Ruby-throated Hummingbird has a much harder time eating insects, because their long bills were designed for slurping nectar, not so much eating and crunching away at insects.
Hot temperatures are just what the Ruby-throats like as long as it is not so hot that the flowers die.

The Ruby-throated Hummingbird loves the sweet flower nectar that comes from different flowers including daisies, tulips and daffodils, to name a few. The ones that were named are usually about the biggest flowers that they visit. This is mainly do to the size and weight of their tiny bodies. Hummingbird gardens are beginning to grow in popularity and they are making the Ruby-throats migration easier. They consist of many different flowers, often flowers that the gardener has chosen and think that will look good in the spot that they have chosen. Usually many varieties are chosen, because there are so many flowers to chose from.
The Ruby-throated Hummingbird mates as soon as it can, once it lands in its summering grounds in the Spring. It really depends on each individual bird to what date they will mate. They mate in Central and Eastern North America. The Ruby- throat always mates in warm temperatures, because it will not return from Mexico until the temperature is warm enough for flowers to be out.

A Ruby-throated Hummingbird nest is mainly made out of plant down, bud scales, covered with lichens, bound with spiders' silk and placed on a small horizontal limb which is approximately three to six metres off the ground. The nest is about two and a half centimetres deep and only about five centimetres wide (just big enough for the mother and little eggs).
Each mother lays one or two white pea sized eggs each Spring. It takes approximately sixteen days to incubate the eggs. Approximately another thirty days later they should be able to fly and go off on their own. All Ruby-throats have to migrate in the fall so that they have a chance at surviving the winter.

Conclusion
The Ruby-throated Hummingbird migrates South, because the flowers on which they depend on. for food, die in the winter. So really it has no other choice, but to migrate to somewhere that has a climate that is warm enough for flowers to grow and insects live. Mexico's average winter temperature is about 1 1 ' Celsius, so vegetation is still able to grow.

They migrate North again in the Spring, because they need to mate and lay their eggs, so that the next generation of Ruby-throats can be ready for the long trip to Mexico in the fall. Some scientists think that they go back to where they were born, so that they can mate. They have to go back to mate, because Ontario's average summer temperature is about 19' Celsius which is warmer than Mexico's average summer temperature, so it is very important for them to come back to North Eastern North America in the Spring.

In 1996, the first Ruby-throat spotted in Ontario was seen on 5/19, the first in 1997 was seen on 5/2 and in 1998 the first seen was on 5/8. By using the data that has been collected from other years, we can make a fairly accurate guess on when we will see our first Ruby-throat. The average date that the first Ruby-throated hummingbird arrives in Ontario, is around the sixth of May, so that has been the date predicted.

I have really enjoyed researching the Ruby-throated Hummingbird. There are so many things to learn about then that 1 would have never thought to look up if I hadn't researched them. I really hope I see some Ruby-throats this year, because that is how I know that this project was worthwhile.