Swallow-tailed Kite spring migration

From: Rex Rowan <rexrowan@gmail.com>
To: Alachua County birding report

As I mentioned in a previous email, the county’s first Swallow-tailed Kites of the spring showed up on the 1st: David O’Keefe saw one over Watson Prairie in the Lochloosa Conservation Area and Fay Baird saw three over Barr Hammock. These are pretty early; more typically we saw the spring’s first in mid-March. The county’s earliest-ever was reported over Paynes Prairie by a fellow named Thomas W. Hicks on 6 February 1954. The next-earliest was one that FWC biologist Craig Faulhaber saw over Prairie Creek on 15 Feb 2014. Sunday’s observations tie the record for the county’s third-earliest sighting.

Anyway, Swallow-tailed Kite biologist Ken Meyer of the Avian Research and Conservation Institute was yet again enlisted to explain the kites’ spring migration route to me.

He wrote, “Our satellite-tracked birds returning to nests in Florida, Georgia, and South Carolina will arrive anywhere on the Gulf Coast, from Florida’s southern shores all the way to northern Mexico and Texas. But once onshore, they immediately turn toward their previous year’s nest sites and travel there as directly as possible over land. The birds seen in the last 5 days in central and northern Florida may include some birds that have nested in these places in the past. If so, they are returning early. But some (what proportion? who knows?) undoubtedly are birds that made landfall north of their South Florida nesting sites and we are seeing them on their way back south to those previously-used nest areas. If a kite leaves the NE Yucatan on strong southerly winds and those winds persist for a couple of days, that bird will fly directly downwind to the earliest landfall, regardless of the direction. They will not peel off early to the east and fly crosswind to, for example, South Florida unless they are passing very close and within sight of South Florida.”

He sent along a map that shows the routes taken by five Swallow-tailed Kites flying north during spring 2014, each represented by a line of a different color: “All 5 colored lines end where their respective birds had nested the previous year. You can see how they make landfall where they can, depending on the best winds, then fly quite directly to last year’s nest site. Seems their best strategy is to get to land as soon as possible, even if this entails an overall longer trip back to the nest area. This means that, to varying degrees, most have to fly with some south in their course to get back down to last year’s site. Most pronounced is the Miami-nesting kite (MIA, in yellow), who is consistently the earliest arrival of our tagged STKIs. Three kites I saw last week near Dade City, Tampa, and Sanibel could have been doing exactly the same thing MIA did in 2014. This is just one small sample of a few of many birds over many spring-times. It’s very representative, though, and makes the key points about STKI’s northbound migration strategy. Another part of the story is that many individuals don’t survive the northbound flight because good tail-winds turn to head-winds part way across the Gulf. Four days is the max any have survived over water. Often they reach that limit relatively close to shore, yet can’t finish.”

I’d been under the impression that kites flew from Yucatan to Cuba and then to SW Florida. Not so much in spring, as it turns out: “Very few over-fly or land on Cuba to any degree going northbound. More do going southbound in the ‘fall’. But even then they don’t necessarily land. Best source of more info on this is our website, www.arcinst.org. We put up news and blogs during both north and south migrations every year, including details on individual birds and links to current maps. There already are 3 blogs on our site for this spring. We start them as soon as the first bird starts north in Brazil.”

Ken adds, “Those interested also will see opportunities to help us keep learning and telling this story. The satellite tracking costs $100/month per bird, and the grants that paid for the transmitters never include more than 1 or 2 years of tracking costs (the kites in the map are starting their fifth year). We have a pledge program called ‘Keep on Trackin” to help us pay some of these bills (we have a ways to go). The alternative is to stop paying and end the data stream (these transmitters are solar-powered and produce 6-8 years of data). We’ve not yet done this, but we’ve reached a point where we have no choice.”

If you want to help this research go forward, it won’t cost you much. You can arrange for an automatic monthly withdrawaI of $10, $20, $30, or more  from your bank account to keep the data coming. It’s painless and it’s important. I signed up for an automatic monthly donation of $20: http://arcinst.org/keep-on-trackin