The Summer Tanager and San Francisco’s Non-Native Plants

One of the more interesting groups to watch, if you like birds, is the Yahoo group SF Birds. (Anyone can read it, but you must join to post in it. [ETA: It’s apparently been changed to a members-only group; only members can read it. This is also true of the links to individual posts, so we’ve taken them out.])  It has over 1,000 members at this writing, but a smaller dedicated group of local birders use it to communicate the whereabouts of rare-in-San Francisco species. Often, someone follows up with links to beautiful photographs. That’s where we found the story of the Summer Tanager.

THE SUMMER TANAGER VISITS SAN FRANCISCO

Summer Tanager, San Francisco. Copyright Mark Rauzon

This is a small songbird that’s a rare winter visitor to San Francisco. The males are a bright red color, the females and immature males are yellow. They feed on insects (bees, wasps and so on) and berries. Recently, birder Alan Hopkins reported seeing a female Summer Tanager [ETA: this link is now accessible only to members] in Golden Gate Park: “… you will find English Ivy growing up some trees. The tanager was catching bees that are feeding on the ivy.

Of course, other birders followed up. Steven Tucker wrote: “…the Summer Tanager was where Alan described it. There are 2 huge columns of ivy adjacent to one another; the
tanager was often in the right-hand clump or in the Eucalyptus trees around it.

Then birder Mark Rauzon posted some wonderful pictures of this little bird in his Zenfolio portfolio. “I found it by it’s ‘churrip’ call at 1:30pm, Monday in the ivy covered Eucalyptus … It was bee-eating and occasionally dropping down to eat blackberries, where I had this face to face encounter.” (The pictures here are reproduced with his permission. They’re copyright. Anyone who wants to use them should check with him at mjrauz@aol.com )

Summer Tanager and Blackberries, San Francisco. Copyright Mark Rauzon

NON-NATIVE PLANTS AS HABITAT

It’ll come as no surprise to birders that non-native plants provide habitat. After all, many of the posts in the SF Bird group describe birds in flowering eucalyptus trees, either for the nectar or the insects attracted to the nectar. (We hope that any birders who still believe eucalyptus trees suffocate birds will check this article, Another Eucalyptus Myth: Bird Death) They mention birds in the blackberry bushes, which provide not only food by way of berries and insects, but excellent cover.  Like the notes above, they mention birds hiding in ivy.

In our article Interwoven and Integrated: Non-native and Native Species in Life’s Web,  we described how native species and non-native species are part of the same functional habitat. This is another example.

  • The eucalyptus (non-native) provides support for the ivy (non-native)
  • which attracts insects (both native and non-native),
  • which become food for the Summer Tanager and other birds (mostly native).

The blackberry bushes work in much the same way; they attract insects, they provide berries, and they provide hiding places. So does eucalyptus – it flowers through the year, and particularly in winter, provides sustenance to birds and insects. (ETA: See the comments below for Monarch butterflies clustering in eucalyptus at Fort Mason in San Francisco.) It also provides nesting spots and cover.

Pointing this up was the most recent post  on the Summer Tanager, from Richard Bradus: “…an immature Red-tailed Hawk alighted, drawing an even dozen Ravens in pursuit. As they rose and flew off the bushes came alive, and out popped the female Summer Tanager. It made a few sorties from the ivy then, after devouring a particularly fat insect (bee?), it retreated to cover.

Summer Tanager eating bee, San Francisco. Copyright Mark Rauzon

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4 Responses to The Summer Tanager and San Francisco’s Non-Native Plants

  1. Pingback: A rare sighting of a Summer Tanager in San Francisco « Death of a Million Trees

  2. webmaster says:

    Monarch butterflies use eucalyptus as a roost on their annual migrations, and recently, San Francisco’s own butterfly expert found a cluster in eucalyptus trees at Fort Mason…

  3. Pingback: Blackberry and Pesticides « San Francisco Forest Alliance

  4. Pingback: Fact Check: Nothing Grows Under Eucalyptus? (Allelopathy) | Save Mount Sutro Forest

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