Friday, April 13, 2012

Insects in New Zealand

Besides great birding, there are some very cool insects in New Zealand.

First off, since we’ve posted monarchs from everywhere else, you might as well see one from New Zealand too. My 2nd cousin Oscar, who is five, was rearing monarch caterpillars. Whenever I stopped at their house, the monarchs were in a different life stage. First I saw tiny caterpillars, about 5mm long. After three weeks, there were a few chrysalises and another was about 5cm and hanging from the leaf in a “J” shape.  The next morning, there was a chrysalis. I left and returned about a week later. The chrysalis was becoming clear, and you can see the monarch’s orange and black wings through it. I had to get on a plane before I could watch it emerge.

Monarch about to emerge from chrysalis, Wellington, NZ

I managed get a bad photograph a dragonfly. Most of them are too fast for me. This is probably a male Blue-spotted Darner. I found it in Miranda in a salt marsh, but you could find this species in Australia as well.  

Adversaeshna brevistyla, Miranda, North Island

In addition to being home to insects from elsewhere in the world, New Zealand has plenty of endemics.

Wetas are basically large nocturnal flightless grasshoppers endemic to New Zealand.  I saw them in the daytime.  They are a very ancient group of insects, and apparently haven’t changed much in the last 100 million years. The Maori word “weta” means something like “demon grasshopper” or “god of ugly things.” Giant wetas are endangered vegetarians too docile to fight and too heavy (at 70 grams!) to jump away from introduced mainland predators. I didn't see any of these big guys--they are pretty much confined to the offshore islands. 

 I did see a young tree weta, probably the Wellington Tree Weta. Check out these crazy long antennae. Tree wetas are fairly aggressive and as adults have big heads with impressive mouthparts, but this is a pretty harmless young one.

Hemideina crassidens, Picton, South Island

I also stumbled upon a cave weta in the woods. Cave wetas are closely related to camel crickets. They don’t have tympanum, but are good at sensing ground vibrations through their feet.  They like caves and other dark places. The one I found was sitting on a path just below tree line.  This is one seriously awesome insect.  

Cave Weta at Tongariro National Park, North Island

Tiger beetles are beautiful and awesome predators.  New Zealand is home to about a dozen species, and this cooperative one that I managed to photograph is called a common tiger beetle.  Lots of these guys were hanging out on some gravel walking paths around the Tongariro National Park, within viewing distance of Mt. Doom. 

Cicindela tuberculata, Tongariro National Park, North Island

I am very good at finding the most common things around, so here’s a photo of a Red Damselfly resting on a dock on Lake Mapourika, South Island. These guys are probably the most common damselfly in NZ. They are native and widespread. 
Xanthocnemis zealanica, Lake Mapourika, South Island

Cicadas spend most of their lives underground as larvae (we all know about the periodical cicadas, some of which spend 17 years underground) sucking on plant roots. When the time and weather conditions are right, they climb up onto some vegetation and out of their old skin.  Like butterflies emerging from a chrysalis, they spend a few hours pumping blood through their wings to straighten them out after being all squished during development. Here is an example of a cicada whose wings were probably stuck in its old exoskeleton when it was trying to do this:

Amphisalta zelandica, Bluff, South Island

As adults, cicadas only live a few days to a few weeks. They die after mating and laying eggs.  This beauty is found from treeline to the sea on the North and South Islands, but is likely a different subspecies on the South island. Thanks to UConn for photographic keys. Hope I got it right. 

Kikihia subalpine, Milford Sound, South Island

I don't know much about weevils, but they're interesting and widespread. In this particular alpine meadow, I found many of these weevils in little tiny flowers.

Weevil on the summit of Mount Stokes, Marlborough Sounds, South Island

Happy Bugging! 

Swallow molt

A little update on what I actually think about/do on a day-to-day basis:

Blue-and-white Swallow (adult), in molt, with helpful labels! near Illimo, Peru

Generally, the life of tropical birds has two large energy expenditures per year: reproduction and molt. In temperate zones, there is also migration for some birds. A bird is therefore faced with striking a balance between these activities in such a way as to maximize its fitness. With hundreds of exceptions, the general rule is that the three events are separated. Take, for example, the Purple Martin. It breeds in MA May-July, then migrates to South America, where it molts all of its feathers (not at the same time!), then migrates back north and repeats the process (if it is lucky). 

Southern Rough-winged Swallow with 6 new, 1 missing and 2 old primaries per wing, Pacora

But why molt feathers in general? The simple answer is that feathers do not last long. And why is this is a big deal? Birds generally have between several hundred (a hummingbird) and over ten-thousand (a swan) feathers on their body… replacing all these is not a trivial investment of protein and energy for the bird – especially for a large one, such as a swan, vulture or albatross. Interestingly, feathers do not grow much quicker in these large birds than in small birds – leading to large birds being constantly in molt in order to replace all their feathers (though there are times where they are in more heavy molt). In a great study, albatrosses in heavier molt were shown to have lower breeding success… one of the only times any trade-off between reproduction and molt has been investigated. 

My guess is that these feathers are only 8-10 months old! Tachycineta stolzmanni, first-year male
Southern Giant-petrel, Ushuaia, Argentina. Big birds are always in molt.

The first day I was here last year, I caught an adult male Tumbes Swallow on a nest who was molting his primaries… After gathering a lot more data both last year and this year, it seems this is the norm. Males begin their molt first, generally the last two weeks of February, followed by females a few weeks later. So my lofty goal this year, which I am working hard on now, is to see if the swallows invest less heavily in reproduction while molting – which I hypothesize to occur because of reduced foraging efficiency in molting birds. Of course, this is taking a long-leap, as this has never been shown, either, but it seems reasonable that a bird like a swallow, which forages entirely on the wing, might have less success or have to expend more energy foraging with missing feathers in the wings.

Strange molt - notice that there is one old feather amidst two new - usually they molt in order. In another study in over 100 specimens of Tachycineta bicolor (Tree Swallow) only 2 examples of this were found.

And just to reinforce the notion that big birds are always in molt. A Southern Screamer, Chascomús, Argentina.

Wednesday, April 11, 2012

Lambayeque rarities and an unidentified hawk

I have been out traipsing around in search of birds to quite a few sites recently and come across some great birds. I will be writing a complete guide to the areas at some point, as I think that information would be valuable to publish online and this seems like the perfect venue for it, but here are just a few teaser pictures of what we have found… and a mystery!
Brown-chested Martin, Progne tapera
There is a small, but seemingly breeding population of Brown-chested Martins at the represa in La Viña, just outside of Jayanca. Schulenberg, et al., mention it in Tumbes near reservoirs and this seems as good a habitat as any, but a bit out of range. Looking at eBird, there are a few reports in scattered locations, but none recently.
This is the mystery hawk:

Sorry about the size/terrible quality - it was far away
Juan Molina and I located it outside of the pueblo of Sauce, near the town of Salas. My first thought was of a Variable Hawk (Buteo polysoma), though Juan immediately thought Short-tailed Hawk (Buteo brachyurus). We both agreed that it had a very well-defined hood, which can be seen in the pictures – we disagree about whether this hood is within the range exhibited by Variable… I think so, he does not. We also did not see a clear-cut tail band while in the field (the pics are useless for that, sorry), which we would expect an adult Variable to have. The bird was soaring on thermals 400+ meters from us and eventually disappeared to the east. I am not sure - it would be an odd Variable, but Short-tailed is really far out of range here.

On that same trip, we located a couple Rufous-winged Tyrannulets (Mecocerculus calopterus), which seem a little bit out of range, but are probably around most of the hills there.

Rufous-winged Tyrannulet, Mecocerculus calopterus
In La Viña, at the represa, we have had good success with Comb Duck (Sarkidiornis melanotos) finding 1-2 per visit. In the guide it is listed as a rare vagrant to coast, though talking to people here, they say it is around occasionally.

Female Comb Duck
Also at La Viña (are you sensing this is a good spot yet?) at least 4 Blue-winged Teal (Anas discors) were present along with several Solitary Sandpipers (not really a rarity, but not too easy to find, either).

Blue-winged Teal, male, with White-cheeked Pintail (Anas bahamiensis)
While not really a rarity, this Zone-tailed Hawk near the town of Algorrobo was a nice surprise – we also found another near the crossing of La Vina and the old Pan Americana.

Zone-tailed Hawk, Algorrobo (near Salas), a life bird for me!

We have found Savannah Hawk four times recently: adults in Poma Tres and Tucume and two separate juveniles in La Viña – one near the cerro and the other at the represa, an individual with a very white head, as pictured.

Juvenile Savannah Hawk, La Viña represa
We also found 3 Least Grebes (no records on eBird in Lambayeque, but surely there are records) and at least 3 Great Grebes at La Viña as well.

Finally, at several spots in the Motupe/Olmos area we have found Dull-colored Grassquits (Tiaris obscurus) and outside of Motupe Ash-breasted Sierra-finches (Phrygilus plebejus) as well.

Tuesday, April 10, 2012

Birding in New Zealand

I promised to write about some creatures from New Zealand when I returned from my travels, but have been exceptionally slow in accomplishing that undertaking.  As an island with only two native mammals—both bats—New Zealand’s bird and insect life have evolved to fill niches normally occupied by rodents, scavengers, ungulates.  Without predation as a selection pressure, several NZ birds have lost the ability to fly.  Everyone knows about kiwis, but there are plenty of other such birds. Examples include an extremely rare parrot, the Kakapo, a large blue-green moorhen-like bird called a Takahe (only about 250 individually remaining), and the more abundant Weka, an enormous rail. Kakapos can’t fly, but climb trees to forage. Go figure. They are also nocturnal. Takahes are grazers; David Attenborough shows them in high alpine fields eating the tasty white part of grasses and discarding the top bit. Wekas forage for insects, grubs, and vegetation.  And then there was the Moa, a huge bird that grazed New Zealand before being hunted to extinction.

Takahe in the Te Anu Wildlife Sanctuary

As well as allowing for flightlessness, the lack of predation in evolutionary time has made many birds are very approachable.  Wekas in particular were unbothered by our presence and boldly approached our campsite to glean scraps of our meals. We tried to discourage such behavior, but it was interesting to see a rail so close.

Weka (western subspecies) trying to steal our dinner.

New Zealand Robins followed us down trails as we stirred up bugs with our feet, and would nearly jump onto our hands if we stirred up the leaves on the side of the path.

After eating bugs around our feet for a few minutes, this Robin
decided to pose nicely where there was actually some light. 

Robins can fly, but many of the flightless birds are suffering now that introduced predators roam New Zealand. Feral cats, stoats, rats, and Australian possums are major problems, but the country deals with them by aggressively trapping, poisoning, hunting, and, in the case of the possum, developing a market for fiber. Possums are killed to harvest their fur; what a great way to manage an invasive species!  Most of the possums I saw were dead, but unfortunately I didn’t even get a photo of roadkill. I did buy some possum yarn. It is very soft and will make great socks for my grandpa.

Back to flightless things. At latitude 47˚S, New Zealand is the closest thing to Antarctica after South America. You might expect to find some penguins. Nine species are found in NZ waters, and some of them breed on the islands. We were able to get a few glimpses of what is touted as the “rarest penguin in the world”—the Yellow-eyed Penguin. They breed in the Catlins, and in late February were onshore, molting (keep in mind that February is late summer in the southern hemisphere).

Yellow-eyed Penguin near Nugget Point

Fjordland Crested Penguins were just starting to molt. We were lucky enough to see one on Monro Beach, an area where about 30 birds nest. They lay two eggs in August and the life-mated pair shares incubation duties.  Chicks get a daily meal of squid, shrimp, octopus, and crab.  By early December they are no longer seen on land, and no one really knows where they go.  An informational panel told us that they usually return around March to molt before disappearing into the sea again.

Fjordland Crested Penguin, Monro Beach, South Island

Little Blue Penguins stick around the colony all year, and we saw a group of around 30 adults return from a day at sea to feed their chicks. They return at dusk in large groups to help escape predation in the water. From a distance they looked like a slow-moving dark log, but as they approached, I could pick out individual heads bobbing along side-by-side. When they reached the shore, the chicks, previously hidden in borrows in the tall grass in the hill behind us, began to make horrendous begging noises. The adults walked uphill to the appropriate burrow, and coughed up some food into the waiting mouths of their chicks. Yum.

For a birder like me (not very experienced, but very excited), five weeks in New Zealand was superb. There are few enough forest birds that I was sure I could ID them all by sight by the time the plane landed. After about a week and a half, I could ID most of them by ear. For the first two weeks at least, I was able to add at least two new birds to my life-list every day. The sea-birds were more challenging, and oddly, we hardly saw any shorebirds until we got to the north island, where we saw close to half of the world population of Wrybill (birds who use their right-curving bills curve to gather food from under rocks while watching the sky for danger) and had about 3000 Bar-tailed Godwits fly over and land 50 feet from us.

100% Pure Awesome.