SEPTEMBER 15 – NOVEMBER 2, 2015
Migration Counts at Curry Hammock State Park will take place from September 15 through November 2, 2015. Visitors can join the counters daily from 9am to 4pm DST. Please link to the Participate page on this site for information.
Funding for Swallow-tailed Kite monitoring during the fall of 2014 was made possible through a gift by Juan Valadez and Laura Roselione. THANK YOU!
Four kite species have been documented from the Florida Keys Hawkwatch count site at Curry Hammock State Park since monitoring started in 1999. These include the Mississippi Kite (Ictinia mississippiensis), the Snail Kite (Rostrhamus sociabilis), and recently for the first time – the White-tailed Kite (Elanus leucurus). However, the beauty and grace emblematic of kites is perhaps best encapsulated in the Swallow-tailed Kite (Elanoides forficatus), an imperiled species that continues capturing our imagination – serving as symbol for wildlife management and conservation agencies throughout the state of Florida – and one that regularly graces the skies of the Florida Keys during fall migration.
- Florida Keys Hawkwatch – Curry Hammock State Park
- Count Site Species Average (1999 – 2013): 18
- Highest Seasonal Count pre-2014 (1999 – 2013): 62 (2008)
- 2014 Total: 256
- Sept. 2-14, 2014: 190
- Sept. 15 – Oct. 14, 2014: 66
- Preseason tally (August 2014) – Middle Keys: 37
All Swallow-tailed Kites breeding in the U.S. are migratory and leave the North American continent during the fall season. Their migratory movements start early compared to other diurnal raptors, and the species is already on the move southward by mid-July.
Few North American hawk migration count sites – like the Florida Keys Hawkwatch – are geographically positioned to allow for the monitoring of Swallow-tailed Kites during the fall. The breeding range of the species (Elanoides forficatus – subspecies forficatus) in the U.S. is now limited to southeastern states, primarily Florida and including portions of coastal Georgia and South Carolina, southern Alabama and Mississippi, and restricted areas in Louisiana and Texas. Despite their breeding throughout much of Florida, population trend assessments are limited by a lack of demographic data.
Unfortunately, the southeast also suffers from a low density of count sites for migratory birds of prey. According to HawkCount.org, the states of Georgia and Louisiana have no reporting, active or existing raptor migration counts. While the state of South Carolina has five registered count sites, none have a history of reporting any Swallow-tailed Kites during migration. The same can be said for two count sites registered for Alabama. In Texas it is a different story. The Smith Point count site overlooking Galveston Bay averages about 83 Swallow-tailed Kites per year over a period of 18 seasons, with as many as 202 kites counted during a single season (2008). Curiously, the Corpus Christi count site averages similarly over 18 seasons, with an average of 82 Swallow-tails per year, and a seasonal high of 349 (2008). The only other fall migration site in Texas reporting in HawkCount – Bentsen Rio Grande Valley State Park – has recorded the species on only three seasons out of 15, with no more than five in 2002. It is important to note that both the Smith Point and Corpus Christi sites start monitoring for raptors in August, and that traditionally, counts in the Florida Keys have not started until September 15, well past the expected peak dates for kites.
As can be seen from the chart above, both of these Texas count sites experience their peak passage dates for the species during roughly the third week of August. With Florida supporting an estimated 60% or more of the entire U.S. population (about 2500 to 4500 individuals at the end of breeding season), the count site in the Keys could expect to detect substantial flights of Swallow-tails starting early August.
While our project has understood that our traditional mid-September start date has resulted in lost opportunities for the monitoring of kites, we have been limited by challenges associated with an expansion of the count season.
The Difference that Two Additional Weeks Can Make
For the fall of 2014, our project made an effort to start the monitoring season significantly earlier than the traditional Sept. 15 start date. In addition to commencing monitoring at Curry Hammock with a full count team on Sept. 2 of this year, pre-season counting efforts were also carried out throughout the Middle Keys, from Long Key to Big Pine Key with the purpose of fine-tuning possible detection locations for greater numbers of Swallow-tailed Kites. The result from 10 days of counting during August 14-31 was 37 detected kites. While several of those birds were observed from various locations in northern Big Pine Key, many of the birds were detected within close proximity to Marathon, or near the hawkwatch count site at Curry Hammock, supporting the concept of adhering to a single site despite the potential for alternate detection locations.
However, the difference was most evident at our count site once full-day (8 hours minimum) operations commenced on September 2. The earlier two weeks of counting allowed us to detect 256 Swallow-tailed Kites (6-10% of the U.S. population), increasing our count 1300% above our site’s average.
As the project proceeds with plans for future seasons, we are encouraged by our efforts from 2014, reassured that counts from August through mid-September should render more kite detections. We will continue working on expanding our count period to include a time-frame better suited for the monitoring of Swallow-tailed Kites.
- Florida Keys Hawkwatch – Curry Hammock State Park
- Count Site Species Average (1999 – 2013): 40
- Highest Seasonal Count pre-2014 (1999 – 2013): 99 (2012)
- 2014 Total: 128
- Sept. 2-14, 2014: 15
- Sept. 15 – Oct. 14, 2014: 113
Although our count site does not experience the number of Mississippi Kites seen in Texas and Central America, it is one of the few sites in North America that documents consistent numbers of the species during the fall. To illustrate the point, most hawk migration counts in the southeast average under two Mississippi Kites each fall season. A notable exception may be Congaree Bluffs in South Carolina, which averages about 15 birds a year, with as many as 76 kites documented in a single season (2003). When you consider the Mid-Atlantic region, no hawkwatch averages more than 2 kites a year according to data submitted via HawkCount.org.
With an average of 40 or more detections, and as many as 128 Mississippi Kites tallied during a single fall season, the Florida Keys Hawkwatch remains the highest count for the species in the eastern U.S.
With an earlier start to the season during 2014, we were able to add 15 birds that would have otherwise been missed during our traditional dates, increasing our highest count by about 30%. Future plans for the lengthening of the season by adding count days during the first half of September – and potentially August – could result in increased opportunities for the detection of migratory Mississippi Kites.
- Florida Keys Hawkwatch – Curry Hammock State Park
- Total: 1 (Oct. 17, 2014)
There has only been one White-tailed Kite documented as part of raptor migration counts in the Keys since standardized efforts started in the late 1980s. While the species breeds irregularly in the Southern Everglades, appearing to prefer the area surrounding Taylor Slough, Chekika and the adjacent agricultural areas in Homestead and Florida City, it is not a common species and little is understood about its life history and population status.
On 10/17/14 at roughly 11 am, the first and only White-tailed Kite detected as part of this project was observed flying southwestward over the Keys land chain. The species has been reported from Monroe County (Florida Keys) in the past, but to our knowledge, this is the only documented record (photo of the described individual above, taken by Kerry Ross).
Although the species tends to remains a year-round resident through much of its breeding range in North America, during nonbreeding season some birds may disperse and this may result in vagrancy and/or range expansion. Little is known about the Florida populations, whether the kites are migratory and/or nomadic.
In North America, the species may be currently experiencing its greatest distribution after a period of expansion. While populations are most concentrated in California, it was nearly extirpated from that state by the 1930s, and extinction had been predicted for the continent around that time.
In Florida, some of the oldest reports (1870s – 1890s) describe birds in the southern Gulf coast, from the area in current-day Naples down through Cape Sable. There are very few modern-day records of the species in that part of Florida. By the 1930s it was thought to be on the verge of extinction in the state, and it wasn’t until the 1980s that the species became established once again in South Florida.
- Florida Keys Hawkwatch – Curry Hammock State Park
- Total: 1 (Sept. 28, 2007)
Only one Snail Kite has been documented from Curry Hammock State Park during migratory raptor counts. Although the species is found from southern Mexico to Argentina, in the U.S. it is limited to restricted portions of Florida, where it is a year-round resident. The species – listed as Endangered in the state and federal registers – is considered nonmigratory, but may respond to habitat changes by engaging in dispersal or seminomadic movements. There is currently no evidence to indicate that Snail Kites regularly fly between Florida and Cuba. However, the species is a common to rare year-round resident throughout much of Cuba.
During September 28, 2007, counters John Van Dort and Cole Wild observed the bird captured in the photograph shown above at roughly 2:10 pm. It is no surprise that this raptor caused initial confusion. The Florida Keys hold very little habitat suitable for Snail Kites, which prefer to forage over freshwater patches in search of their preferred food – snails of the genus Pomacea. While reports from the Everglades include brackish tracts from Paurotis Pond to Flamingo, the species is virtually undocumented in the Florida Keys.
For more information about the status and movements of Snail Kites, Swallow-tailed Kites and other bird species found in Florida, visit the Avian Research and Conservation Institute‘s website.
At least 3 Bahama Swallows (Tachycineta cyaneoviridis) were seen this afternoon (October 26) at Curry Hammock State Park – with the first bird – an adult – detected at roughly 2:30 pm. Photographs of individual juvenile and adult birds were captured from the Florida Keys Hawkwatch deck. The birds were seen feeding in relative association with other swallow species, including Barn, Northern Rough-winged and Cliff. One Cave Swallow was also seen this day. Above, an adult photographed by Kerry Ross.
We continued seeing the Bahama Swallows foraging over the adjacent campgrounds well past 4:30 pm. Photo of a juvenile above by Alexander Harper.
From October 20 through the 24th, we experienced much rain and wind associated with a tropical depression brewing in the Gulf of Mexico – see the “Huge Passerine Movement” blog entry for more information. While we were experiencing large daily flights of swallows earlier in the fall, these have greatly diminished as the season has progressed. During this recent tropical depression, we struggled to tally a combined number of swallows in the three digits. After the rain dissipated and clear weather associated with winds out of the north dominated the skies, more swallows certainly pushed through. By contrast, on October 25 we counted 783 swallows, and today Oct. 26 we counted 513. Above, photo of an adult Bahama Swallow by Kerry Ross.
It must be noted that the Bahama Swallows from Curry Hammock were not isolated occurrences. On this day, the species was also observed and documented from Cape Florida (Key Biscayne) at around midday. Additionally, a Bahama Swallow was reported from Long Key State Park on Oct. 25 – 11 miles northeast of Curry Hammock. The photo above, and the 3 below were taken by Kerry Ross at Curry Hammock.
The Bahama Swallow is endemic to the Bahamas and it is common on Andros, Abaco and Grand Bahama. It is considered a very rare visitor to South Florida, with under 10 documented records prior to these occurrences. All the prior records took place before 1993.
From October 20 – 24, we counted 10,311 passerines migrating over the Keys!
During this period, the Florida Keys were pounded with a tremendous amount of rain and wind associated with a low pressure system that gained strength in the Gulf of Mexico and pushed continuous thunderstorms, showers and strong gusts into our area.
We continued conducting our morning transect counts at Long Key, even during periods of heavy rain, often experiencing persistent movements of birds along the coast.
On October 24 alone, we counted a total of 4,948 passerines, 4,623 of which were warblers! While it may have been remarkable to have experienced over 200 Black-throated Blue Warblers that morning – which we did – a greater surprise was that a vagrant Northern Wheatear (Oenanthe oenanthe) was found along the beach at Long Key!
Believe it or not, elevation plays a huge role in the type and occurrence of habitats in southern Florida and the Florida Keys. In the interior of South Florida, for example, the highest points are pine or oak dominated woodlands. Drop three or four feet in elevation, and you’ll be in a cypress dome or wet marl prairie (the latter being true Everglades). The mangrove forests that line the coast are yet another patent habitat associated with the region. Yet there is another important but lesser-known ecosystem in extreme South Florida and the Florida Keys that recalls more of a West Indian influence: tropical hardwood hammocks.
A hammock in this use of the word describes a dense hardwood stand of trees bordered by a wetland. And a tropical hardwood hammock, more specifically, is a forest comprised of tree species such as Gumbo Limbo, Poisonwood, Blolly, Wild Dilly, and Pigeon Plum, among others. In the Keys, it is often the habitat just inland from the mangroves of the coastline and estuaries.
If you visit Cuba, Hispaniola, The Bahamas, and even coastal Yucatan Peninsula, you’ll see that the flora of the tropical hardwood hammocks of extreme peninsular Florida and the Keys are more similar to the Caribbean than to the flora of other parts of temperate Florida. This is also apparent in the relationship between the bird species. For example, “specialties” of the Keys such as the White-crowned Pigeon, Mangrove Cuckoo and Black-whiskered Vireo are best found in the dense hammocks of the Keys. If you were to visit Cuba or the Bahamas, you would see these species breeding and foraging in nearly the same tree species.
The same goes for migrating passerines. During the fall at Long Key State Park, where there are a few parcels of hardwood hammocks, we see some of the highest numbers of migrants using the hammocks to rest and forage. The fruiting trees and shrubs have proven to be extremely important, perhaps even vital to large numbers of migrating thrushes, vireos and flycatchers. American Redstarts, Worm-eating, Black-and-white, and Black-throated Blue Warblers are among several species of warblers that can often be found deep in the interior of a hammock’s middle and upper stories, while Ovenbirds, Swainson’s and Kentucky Warblers comb the ground level where there is often very little sunlight penetration. Common Nighthawks and Chuck-will’s-widows seem to rely heavily on this habitat for roosting during migration.
Along with a menagerie of breeding and migrating species, there have been several that were certainly not expected. Within the state park just in the second half of September of this year, this habitat has accommodated three exceptional vagrants: Key West Quail-Dove (9/27/14), Yellow-green Vireo (9/24/14), and Sulphur-bellied Flycatcher (9/17/14). The quail-dove and the flycatcher frequented the Golden Orb Trail, while the vireo was located in a nearby restricted area where the Florida Keys Hawkwatch team has been granted permission to survey.
As touched upon before, the botanical composition of a hardwood hammock in the Keys is nearly a mirror image of those found elsewhere in the West Indies. If you were to examine and compare the North American bird species that winter in hardwood hammocks in Cuba and the Yucatan, you’d also see that there is a lot in common with extreme southern Florida and the Keys (i.e. the Black-throated Blue Warbler). Similarities in climate between the Keys and the West Indies help explain how this is possible, but here is some literal food for thought: birds are often vehicles for transporting seeds and berries to foreign locations. It is likely that the strong-flying and exploratory White-crowned Pigeons helped aid the colonization of many of the plants found in the Keys. Fruit ingested by a pigeon gorging in a hardwood hammock in Cuba might have come out the other end in the Keys after a hop over the Straits of Florida, an easy flight for a pigeon. Or maybe the secretive and unforthcoming Key West Quail-Dove, which historically may have bred in the Keys, also played a role?
However, there is no denying the threats to such a unique and spatially restricted habitat. In the Keys and coastal South Florida, any dry land is prime real estate for humans. Much of the developed areas of the Keys were historically hammocks, and tracts of this West Indian habitat are now more-or-less restricted to protected areas. Human encroachment has fragmented this highly valuable habitat up and down the Keys, but the hardwoods of Long Key State Park are still very much for the birds.