Creating a wildlife haven one plant at a time

Monday, March 25, 2013

Hummingbird Migration Season

Spring may be slow to start but don't tell the birds that. Spring migration season is getting underway.

So, why do hummingbirds migrate?

Hummingbirds are largely tropical birds but have expanded their ranges to exploit rich temperate food resources and nesting space. Long ago they found lots of unoccupied niches in the U.S. and Canada that allowed them to avoid the intense competition in the tropics.

Ruby-throated hummingbird

Research from banding efforts and citizen science projects, is showing that more and more hummingbirds are being reported year-round in North America from the Pacific coast through Arizona, along the Gulf coast and into the Southeast. In fact, this winter Georgia Hummers has banned and documented over 100 hummingbirds in Georgia. 

As my regular readers know, two rufous hummingbirds (one male, one female) arrived in our garden late last fall and overwintered here. For my post on the banding process click here.

 Male rufous
Look how brown he has become since he was banded in December 2012.

These two rufous hummers should be migrating to their summer breeding grounds soon. Their migration route from the Southeast to the Pacific Northwest/southern Alaska is unknown but often they follow in the heels of the sapsucker woodpecker migration. One theory being studied is the correlation of Spring migration to leaf-out times. Birds that rely on insects may start migrating when the leaves appear because it corresponds to the availability of the millions of insects the birds need to eat.

Is he sticking his tongue out at me or catching bugs?

Hummingbirds are omnivores. Nectar is just the fuel to power their insect catching activity. They depend on insects that are not readily available in subfreezing weather so most of the hummers go back to their tropical home during winter months.

That butterfly up there might make a good snack

Are hummingbirds wintering in the Southeast 
more frequently than in the past?

Hummingbirds are one of the least studied birds but more is being learned about them every year. For example, before 1998 there were no documented Calliope hummingbirds in Georgia. Over the past 15 years, it has become a regularly occurring winter species with over 20 birds banded and several returning multiple years. The Georgia Ornithological Society Checklist and Records Committee has voted to take Calliope Hummingbirds off the review list! (source: Georgia Hummers)

Some species of hummingbirds, like the Rufous, are tough little birds.  They are much more adapted to cold temperatures where freezing nights are common even in their summer stomping ground; unlike, the Ruby-throated hummingbirds (RTH) who don't handle the cold as well because they don't go in and out of torpor as readily as other species of hummers. Therefore to avoid the cold and scarcity of food they go south. In the Southeast, Rufous survive on nutrients from Sapsucker holes (see my post here for more on this subject) and insects that fly around on warmer days in addition to nectar sources from feeders.

How do hummingbirds know when to go?

Hummingbirds migrate in response to hormonal changes that are triggered by the length of day. Keeping feeders up or having a natural food sources available late into Fall will not entice hummers to stay. In fact taking feeders down will result in hummers feeding elsewhere and they may not bother to return to your garden the following year.

a first year RTH

Migration is an instinctive behavior and each hummingbird species has its own migration strategy. The RTH begin their remarkable Spring migration northward across the Gulf as early as January but more typically in February and as late as March. They usually leave at dusk for their non-stop flight, of up to 500 miles, which takes between 18 to 20 hours depending on the weather. Before they begin this long trek they will pack on fat and almost double in size from 3.25 grams to 6 grams. By the time they reach the U.S. shores they will only weigh 2.5 grams!


New research out of Clemson, Taylor and Nebraska University show that RTH are arriving 12 to 18 days earlier than in past decades. The study contributes this to warmer temperatures. Warmer temperatures would influence availability of food which is a key factor in migration timing.

Photo: Clemson University

But according to James Van Remsen, curator of birds at Museum of Natural Sciences at LSU, what really counts biologically, is whether the peak period of migration has changed. That would mostly likely affect population biology.



 Food = Energy, Energy = Life

Hummers are solitary birds and don't rely on one another to survive. They are very intelligent birds and will remember year over year where every feeders hangs at their home base and along their migration path. They also know every flower within their territory and how long it takes that flower to replenish its nectar. Hummingbirds divide themselves by territory. Territories are chosen based on nectar, water and food availability. Most male territories are about a quarter of an acre. Females define their territory by their nesting site. Both male and female will aggressively defend their area.



Because of their inquisitive nature they readily spot food sources and dive in to stake their claim. Hummingbirds have been known to hang around the same feeder the entire day just to guard it. It is a good idea to hang more than one feeder in your garden. Either hang them bunched together (one hummer can't possibly guard them all) or space them far apart. Also plant a selection of nectar plants that are pollinated by hummers.

The RTH should be arriving any day now. It will be very interesting to see how well the Rufous and RTH "play" together if they are here at the same time.  Will one chase off the other? Stay tuned...

34 comments:

  1. Oh Karin, I am loving these hummingbird posts! You are so knowledgeable about them. I learn something new each time I visit. I can't wait to hear about how the RTHs and Rufous interact.

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    1. Beth, I am so glad that you found this post informative. It is funny how attached one can get to wild birds but I have been very spoiled having hummers in our garden for an entire year now. They are so chatty and energetic they bring a special atmosphere to the garden. The rufous have their favorite hang out spots including the knock out roses which really need to be pruned but I am leaving them for the hummers.

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    2. Karin: I added your "Lessons Learned" post to the wrap-up. I checked back at the beginning of the month, and realized that you had done a post for the meme. I remembered seeing it, but I didn't have a link for it. But now it's all set. Thanks so much for your participation!

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  3. Really good and comprehensive article, Karin. You seem to be right saying they have found niches further north than their tropical range. It seems that there is more and more of them in the last few years. I did notice them everywhere in the tropics though. Very nice photos of them, BTW. They are not easy to get good images either.

    One thing different between the tropical ones, they are far more colorful. I think I only identified one species correctly of the ones I photographed. In fact some of the prettier ones were impossible to capture. They were too fast and afraid.

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    1. Donna, indeed they are challenging to capture on camera. It certainly doesn't help that they don't sit for long and pump their wings so incredibly fast. The rufous have been more difficult to capture since they don't let me get as close to them as the RTH. The RTH seem more comfortable around humans and have different personalities.

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  4. Amazing that you get photos of these little guys and how wonderful that you had a couple Winter over in your gardens.
    Cher Sunray Gardens

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    1. Thanks Cher! Lots of patients to get them when they are sitting still for all of two seconds, LOL! It has been an amazing experience hosting the rufous. I hope they come back next year!

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  5. Great hummingbird pictures!! And a very informative piece.

    I haven't seen Rufous Hummingbirds here, but we do get a lot of RTHs each year. They usually show up when the Eastern Columbine starts blooming. And they do love their Brazilian Blue Sage!

    You asked about the voles and the pink primrose -- I don't think the voles go after the primrose as much because the primrose doesn't have fleshy roots, and if they do at some point I'm hoping the primrose can outgrow the voles' appetites!

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    1. It is cool to read about your experience of the RTH showing up to coinside with bloom time of one of their nectar plants. Thanks for the response about the voles. They have gone after woody plants in our garden before. :(

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  6. Thanks for all the great info. I'm wondering if I need to put feeders out.

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    1. Yes, put your feeders out. Journey North has a map where people report their first RTH sightings. You can use it to determine when to put out your feeders. http://www.learner.org/jnorth/maps/humm_ruby_spring2013.html

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  7. Great post! We only have the RTH, but I definitely noticed more of them last year. Not sure if that is because of changes in the garden or the general population. I really enjoyed your photos, they've got me eager for the hummingbirds' return!

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    1. We had more hummers last year too. Like you, not sure if it is that we add more and more nectar plants and improve the general habitat of our garden for wildlife or other factors. I hope you have lots of hummers this year Jason!

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  8. Wow! What a great post!! I've never seen many hummingbirds in my area. Until last year! Then I spotted them in our back yard. We have several plants that seem to attract them, but I also hung a feeder. Guess I better fill the feeder :-)

    Jocelyn @ http://justalittlesouthernhospitality.blogspot.com

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    1. How exciting Jocelyn! Often hummingbirds come back to the same place so hopefully you will see them back this year. Keep planting plants they love and they will come! So glad you left a comments. It is nice to hear from new visitors. Will pop over to visit your blog now.

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  9. Amazing photographs and great information here. I hadn't thought of the fact that flowers need time to replenish their nectar. Now that I know, it's obvious that would be important information for the birds to remember but amazing that they do remember this.

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    1. Plants are so fascinating and scientists are learning so much more about the dynamic between plants and animals. The fact that they communicate with each other is mind blowing!

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  10. Very informative post! And as always--great photos (love your blog header photo too!)...

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  11. Karin your pictures are incredible. I won't see the hummers until mid to late April. Mine do not like the feeders but perhaps I will try again. When the garden is really blooming I will see several hummers flitting around and sharing the garden...well sharing most of the time. Interesting and fascinating post!

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    1. Perhaps you have enough nectar plants for them and bugs that they ignore the feeders. It would be interesting to know if hummers prefer blooms to feeders if they had a choice. I would still put up some feeders. Maybe you will get even more hummers. It may take time.

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  12. All the information you have provided about hummingbirds is fascinating. They really are amazing little birds.

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    1. Indeed, they are special. I am savoring all the time in the garden that I hear the rufous chatting because it won't be long before they leave. I am keeping my fingers crossed they survive and return to my garden next winter.

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  13. I am continually impressed by how much you know about wildlife. :o) I knew hummers had episodic memories and would remember the location of gardens, feeders, etc as episodes to be repeated if they returned. I have hummers every year and have increased the number of plants in the garden that support them. I always feel honored when they arrive in the spring. :o)

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    1. Me too! I get so excited I do a little dance to celebrate!

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  14. I love seeing your photos and hearing about the lives of these magical little birds - we're not lucky enough to have them over here so these posts mean so much!

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    1. I am so glad you enjoy them! It is hard to describe how much vibrance and energy they bring to the garden but their presence always puts a smile on my face.

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  15. This really is wonderful article ! I simply love’d it !

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  16. You had many bits of interesting information in your post Karin. I thought that the research out of Clemson, Taylor and Nebraska University showing that RTH are arriving 12 to 18 days earlier than in past decades particularly interesting. It is also interesting to know how territorial and smart these birds are.
    Spring has been delayed here as it has been in so many places, but I knew that it had finally arrived because of the birds. There is now birdsong to wake us up each morning. I look forward to the arrival of the hummers in a few months time.

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  17. I don't know how one makes it happen, Karin,but it seems to me that your photos should be published somewhere. Or, perhaps they are?

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  18. I live in Henderson, NV. I have three nests in my yard and one in the front. But I have been no females yet this year. I have two males that live here year round. But I haven't seen any new birds. Anybody seen them in Nevada?

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  19. I live in Henderson, NV. I have three nests in my yard and one in the front. But I have been no females yet this year. I have two males that live here year round. But I haven't seen any new birds. Anybody seen them in Nevada?

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  20. I saw my first hummingbird of the year on Monday 4/7/2013 it was visiting the coral hunneysuckle, in spite of the cat lying in the shade under the vine... Cheeky buggers...
    It headed for the patch of eastern columbine... B4 I could reach for a camera...

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"Don't wait for someone to bring you flowers. Plant your own garden and decorate your soul"

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